Septic in Loganville, GA

Last updated: Mar 21, 2026

In Loganville, where tree-lined streets meet family life and busy weekends, your wastewater system is a quiet but crucial part of keeping a home comfortable and safe. You'll often find that on-site septic is the practical, reliable choice for many local properties, working behind the scenes so your daily routines stay smooth.

Is septic common in Loganville? Yes. In Walton County and throughout many Loganville neighborhoods that aren't tied to a municipal sewer line, septic systems are the norm. Some newer sections closer to town do connect to public sewer, but a solid share of homes still rely on their own tank and drain field. Should you expect septic if you own or buy a home? If the property isn't served by a sewer main, plan for a septic system as part of the home's setup and ongoing maintenance. When buying, ask for seller disclosures, verify there's a septic tank and drain field, and arrange a professional inspection and pumping history as part of your due diligence.

Why do homes use septic systems in Loganville? A few practical realities shape the choice:

  • Many lots are sized for yards and privacy rather than sprawling municipal lines, making sewer connections costly.
  • Soils in parts of the area can be well-suited for a properly designed septic field, provided installation and placement are done by a qualified pro.
  • Local development patterns kept sewer expansion uneven, so on-site systems remain a common, sensible solution.
  • Homeowners often prefer a predictable maintenance schedule and the independence of managing their own wastewater system.

High-level explanation of why septic exists here: Septic systems exist because, in much of Loganville, the combination of soil, lot size, and the cost of extending city sewer makes on-site treatment the practical, economical choice. A typical system uses a tank to separate solids from liquids and a drain field to distribute treated water into the soil. When sized correctly and kept in good shape, it's a quiet, long-lasting setup that supports a busy family home.

Maintenance basics to keep in mind:

  • Pump every 3–5 years (or per the pro's recommendation) to remove built-up solids.
  • Conserve water to reduce load on the system.
  • Avoid flushing wipes, grease, solvents, or harsh chemicals.
  • Protect the drain field from heavy equipment and landscaping over the area.
  • Schedule regular inspections to catch leaks or soggy spots early.

With this groundwork, you'll have a solid starting point for keeping your Loganville septic system healthy.

Where Septic Systems Are Common in Loganville

Map of septic coverage in Loganville, GA

Loganville sits on the eastern edge of Gwinnett County, a mix of suburban neighborhoods and rural pockets. Because sewer lines don't reach every corner yet, septic systems remain a practical and common solution for many homes. Here's a practical look at where you'll typically find septic in Loganville and why.

Where septic systems are most common

  • Areas outside current sewer service boundaries. If your property sits beyond the county's planned sewer footprint, a septic system is often the default wastewater option.
  • Older neighborhoods with larger lots. Homes built on half-acre or larger parcels frequently relied on septic before centralized sewer expansion, and many still do.
  • Rural and semi-rural pockets. Properties that were developed with private wastewater systems or limited public infrastructure tend to use septic more than newer, densely developed areas.
  • Hills and soils that complicate mainline sewer extensions. In some spots, soil conditions or drainage patterns make on-site treatment more practical than costly mainline expansion.

Why Loganville patterns look this way

  • Development history. Loganville's growth over decades created areas served by public sewer and other areas that were never economically included in extension plans.
  • Infrastructure costs. Extending sewer mains to distant lots can be expensive, so septic remains a sensible, cost-effective option for many homeowners.
  • Soil and groundwater considerations. Local soil types and groundwater depth influence septic design and feasibility, which keeps septic popular in certain zones.

Common septic system types you'll encounter

  • Conventional gravity systems. The most common residential setup when soil and space permit.
  • Alternative designs for challenging sites. In areas with shallow soil, high water tables, or restrictive topography, you'll see mound systems or other specialty on-site solutions.
  • Drainfield variations. Depending on lot size and setbacks, drainfields may be standard trenches or specialized layouts to fit the property.

How to verify whether your home uses septic

  1. Check your property records. Look at the deed or tax records for notes about "septic" vs. "public sewer."
  2. Inspect your yard for access features. Many septic systems have a visible lid or riser near the rear or side yard, plus a cleanout near the house. A licensed professional can locate and map the system if you're unsure.
  3. Contact the right local and state agencies. If you're unsure about sewer service in your area, call Gwinnett County or check their official site for service maps and boundaries. For state guidance on on-site wastewater, see the Georgia EPD and Department of Public Health resources below.
  4. Hire a licensed septic contractor for confirmation. A qualified professional can confirm system type, location, and condition, and perform a recommended maintenance plan.

Quick maintenance reminders for Loganville septic areas

  • Pump every 3–5 years for most residential systems, or as advised by a professional based on usage and tank size.
  • Do not pour fats, oils, or harsh chemicals down drains; they can disrupt beneficial bacteria and clog the system.
  • Keep heavy equipment off the drainfield area and avoid planting deep-rooted trees or shrubs directly over the tank or leach field.
  • Schedule regular inspections after major changes in water use (new family members, remodeling, etc.).

Official resources

Septic vs Sewer: What Homeowners in Loganville Should Know

Septic systems (on-site) basics

  • An on-site septic system treats wastewater on your property, typically consisting of a septic tank and a drainfield. Wastewater flows from the house into the tank; solids settle, scum forms, and clarified water exits to the drainfield for further natural treatment.
  • Life and performance depend on design, soil conditions, and maintenance. With proper care, a well-built system can last 20–30 years or more.
  • Important maintenance concept: never ignore unusual drains, odors, or standing water in the drainfield area. Early signs can prevent costly repairs.

How municipal sewer works

  • In a sewer system, wastewater is collected through underground pipes and sent to a centralized treatment plant operated by a city or county utility.
  • Homeowners pay a regular utility bill for service, and the utility covers the network's operation, maintenance, and most repairs.
  • Availability depends on service areas; not every parcel in Loganville is currently connected. If sewer is available, many jurisdictions require tying in or offer a financial incentive to connect.

Availability in Loganville

  • Loganville spans areas served by Gwinnett County's sewer network and areas that rely on on-site septic. Availability can vary by neighborhood, subdivision, and lot.
  • To confirm whether sewer is available for your property:
    • Contact the local utility or county department that handles sewer service.
    • Check property records or your closing documents for sewer easements or connection requirements.
    • Review subdivision maps or reach out to the local planning or public works office.

Costs and long-term considerations

  • Septic system
    • Up-front costs: design, permitting, and installation.
    • Ongoing costs: regular pumping every 3–5 years, inspections, and occasional component repairs.
    • Major repairs or drainfield replacement can be substantial but are infrequent with good maintenance.
  • Municipal sewer
    • Up-front costs: possible connection or tapping fees if you aren't already connected.
    • Ongoing costs: monthly or quarterly sewer bills that cover system maintenance and capital projects.
    • Availability of service means fewer on-site surprises, but bills can rise with rate adjustments.

Maintenance basics

  • Schedule and document regular inspections (frequency depends on tank size and household usage).
  • Pump the septic tank as needed (commonly every 3–5 years). More occupants or heavy use may require more frequent pumping.
  • Protect the drainfield: avoid parking on or driving over it, keep heavy equipment away, and plant only shallow-rooted vegetation nearby.
  • Use water wisely and choose septic-safe products. Avoid flushing chemicals, oils, solvents, or non-biodegradable items.

Pros and cons at a glance

  • Septic on-site
    • Pros: potential lower long-term utility costs; direct control over maintenance; usable where sewer isn't available.
    • Cons: ongoing responsibility for maintenance and repairs; upfront installation costs; risk of failures if neglected.
  • Municipal sewer
    • Pros: predictable monthly bills; utility handles major maintenance and repairs; no drainfield concerns.
    • Cons: service is location-dependent; rates can rise over time; reliance on external infrastructure.

Quick steps to make a decision

  1. Confirm your current system type and whether sewer is available at your property.
  2. Estimate long-term costs for septic maintenance versus sewer bills and potential taps.
  3. Consider resale implications and potential transfer inspections for septic systems.
  4. Check official resources to understand local regulations and best practices.

Official resources

  • EPA. Septic Systems:

Typical Septic System Types in Loganville

Conventional gravity-based septic systems

This is the workhorse for many Loganville homes. A buried septic tank receives household wastewater, and effluent exits by gravity into a drainfield where soil and bacteria treat it before it returns to groundwater.

  • How it works:
    • Wastewater enters the tank; solids settle, scum rises, liquids move to the drainfield.
    • The drainfield uses perforated pipes buried in the soil to distribute effluent for natural treatment.
  • When it fits:
    • Adequate soil depth, good drainage, a reasonable groundwater level, and a stable lot with space for a drainfield.
  • Pros and cons:
    • Pros: Simple design, generally lower upfront cost, easy to service.
    • Cons: Requires regular pumping and proper maintenance; performance declines with misuse or seasonal wet conditions.
  • Maintenance steps (3-point plan):
    1. Schedule a professional pump-out every 3–5 years (or per local guidance).
    2. Use water wisely to limit solids and keep system buffers intact.
    3. Protect the drainfield: keep heavy vehicles off it, plantings away from the area, and avoid chemicals near the field.
  • Planning steps for Loganville homes:
    1. Obtain a soil evaluation to confirm suitability.
    2. Work with a licensed septic designer to size and layout the system.
    3. Have the system permitted by the local health department before installation.

Learn more: https://www.epa.gov/septic

Alternative and enhanced wastewater treatment options

If soils are shallow, high in groundwater, or have limited drainage, alternative systems provide reliable treatment with engineered features.

  • Aerobic Treatment Units (ATUs)
    • How they work: Add controlled oxygen to accelerate bacterial treatment inside the tank.
    • When used: In problematic soils, with limited space, or where higher treatment levels are needed.
    • Maintenance: Requires electricity, regular servicing, and occasional replacement of aerators and clarifiers.
    • Pros/cons: Higher treatment efficiency; more components to maintain and monitor.
  • Sand mound systems
    • How they work: A raised mound with sand underneath the drainfield provides a suitable treatment medium when native soil won't support a conventional drainfield.
    • Pros/cons: Effective in poor soils; typically higher initial cost and longer permitting process.
  • Pressure distribution and pumped effluent systems
    • How they work: A pump distributes effluent under pressure to multiple laterals for uniform loading.
    • Pros: Reduces the risk of a single clogged section and works on challenging properties.
  • Drip irrigation and evapotranspiration (ET) systems
    • How they work: Treated effluent is applied through emitters or ET beds to manage moisture and reuse water.
    • Pros/cons: Efficient water use; more complex maintenance and monitoring.

Learn more: https://epd.georgia.gov, https://dph.georgia.gov

Mound and specialized drainfields

  • Mound systems
    • When used: For sites with shallow bedrock, poor native soil, or high groundwater that prevents standard drainfields.
    • How they work: An engineered raised drainfield sits above the natural soil, using imported sand for treatment.
    • Maintenance: Regular inspections and proper loading to protect the mound structure.
  • Sand filtration beds
    • How they work: Treated effluent passes through a sand filtration layer for additional polishing before final disposal.
    • Maintenance: Routine inspections and system-specific service intervals.

Learn more: https://www.epa.gov/septic

Common Septic Issues in Loganville

Drainfield Saturation and Soil Incompatibility in Loganville

  • Signs to watch for: persistent damp areas in the yard, a strong sewer odor near the drain field, slow drains, or gurgling sounds from plumbing.
  • Loganville-specific factors: parts of Gwinnett County, including Loganville, sit on soils with clay content and variable depth to groundwater. Heavy rainfall and seasonal wet periods can saturate shallow drain fields, making absorption and evapotranspiration less effective.
  • What to do (steps):
    1. Limit water use during wet periods (spread out laundry, avoid long showers, skip unnecessary irrigations).
    2. Have a licensed septic pro evaluate the system. They may perform a dye test, a drain field inspection, and a tank pump if solids are near the outlet.
    3. Consider a field upgrade or treatment alternative (e.g., an aerobic treatment unit or a larger/alternative drain field) if the site soils and space allow.
    4. Protect the drain field from compaction and root intrusion; plant only shallow-rooted vegetation over the area.

Tree Roots and Drainfield Damage

  • Signs to watch for: backups, toilets not flushing completely, or cracks and settlement on the septic tank lid or concrete apron.
  • Why Loganville matters: many homes in the area have mature trees moving closer to septic beds over time; aggressive roots can invade pipes and the drain field, reducing absorption capacity.
  • What to do (steps):
    1. If roots are encroaching, consult a licensed professional about root barriers or rerouting accessible lines.
    2. Avoid planting trees or large shrubs directly over the drain field.
    3. Schedule an inspection if you notice repeated backups, even after pumping.
    4. Consider regular camera inspections to detect root intrusion early.

Aging Tanks and System Components

  • Signs to watch: frequent sludge buildup, odors, slow drains, or backups even with normal water use.
  • Loganville context: many homes in older Loganville neighborhoods were built several decades ago, so tanks, baffles, and distribution boxes may be nearing the end of their design life.
  • What to do (steps):
    1. Schedule pumping and a professional inspection if you haven't had maintenance in a while.
    2. Have baffles, inlet/outlet tees, and the distribution box checked for leaks or wear.
    3. Plan for component replacement or system upgrade as recommended by a licensed septic contractor.
    4. Keep maintenance records; upgrade options vary by site conditions and local code requirements.

Water Overload and Solids Management

  • Signs to watch: backups after heavy laundry days, slow drains, or unusually frequent pumping needs.
  • Local factors: GA summers and lawns often require irrigation; abundant household water and disposal of solids (like coffee grounds, grease, or disposables) can overwhelm the system more quickly.
  • What to do (steps):
    1. Stagger high-water-use activities (laundry, dishwashing) and avoid long showers during peak times.
    2. Install water-saving fixtures (low-flow toilets, faucets) and use a disposal-free or disposal-minimized approach.
    3. Avoid flushing non-septic-safe products; use septic-safe cleaners and cleaners in moderation.
    4. Schedule pumping every 3–5 years or as recommended by a local pro, especially for older systems.

Maintenance Gaps and Prohibited Products

  • Signs to watch: unexplained odors, wet spots, or sudden changes in drain performance.
  • Loganville note: homeowners who neglect scheduled maintenance or rely on harsh chemicals can harm beneficial bacteria and shorten system life.
  • What to do (steps):
    1. Maintain a pumping and inspection schedule with a licensed professional.
    2. Use septic-safe detergents and avoid chemical drain cleaners.
    3. Keep a simple maintenance log (dates of pumping, inspections, and any repairs).
    4. Keep garbage disposals to a minimum to reduce solids in the tank.

Flooding, Water Table, and Seasonal Effects

  • Signs to watch: yard pooling, slow or no infiltration after heavy rain, backups during storms.
  • Loganville factor: heavy rain events and seasonal floods can raise the water table and saturate the drain field.
  • What to do (steps):
    1. Do not drive or park on the drain field during wet conditions.
    2. Ensure proper grading around the system to divert surface water away from the field.
    3. If you notice repeated issues after storms, have the system evaluated for field health and drainage improvements.

Helpful Resources

  • EPA: What is a septic system and how it works
  • Georgia Department of Public Health (Environmental Health and Onsite Sewage programs)

Septic Inspection, Permits & Local Oversight

Who oversees septic systems in Loganville

  • Georgia sites statewide standards through the Georgia Department of Public Health's Onsite Wastewater Management Program. Local health departments handle permits and inspections.
  • For Loganville, determine jurisdiction based on location:
    • If your property sits in Gwinnett County, contact the Gwinnett County Environmental Health office for permits and inspections.
    • If any portion lies in Walton County, reach out to the Walton County Health Department.
  • Quick checks to confirm who oversees your property:
    • Look up your property parcel map or deed.
    • Call the county environmental health office to confirm permit requirements.
    • See the state on-site wastewater page for general guidance.

Permit requirements in Loganville

  • Typical permit requires for:
    • New onsite septic system installation.
    • Replacement of tanks, drainfields, or major components.
    • Substantial repairs or modifications that change the design or capacity.
    • Moving the system, changing its purpose, or relocating components.
  • Routine septic pumping, cleaning, and most maintenance tasks usually do not require a new permit, but maintain records of service.
  • Always use a licensed onsite system designer or contractor for design and installation. Improper work can lead to inspection failures and costly remediation.

The permit process (step-by-step)

  1. Engage a licensed onsite designer/contractor to perform a site evaluation and design.
  2. Gather required documents (site plan, soil test results, system design) for submission.
  3. Submit the plan package to the appropriate county health department for review.
  4. Health department reviews for code compliance and feasibility; respond to any requested changes.
  5. When approved, obtain the septic permit and any conditions or variances tied to the project.
  6. Schedule and complete installation according to the approved plan; adhere to setbacks and drainage rules.
  7. After installation, arrange the final inspection and obtain final approval and system registration.
  8. Important: never begin work without an issued permit.

What inspectors look for during inspection

  • Correct sizing and placement of the soil absorption area.
  • Proper tank integrity: watertight tanks, correct baffles, and appropriate tank dimensions.
  • Correct installation of distribution components, effluent filters, and cover material.
  • Compliance with required setbacks from wells, foundations, surface water, and property lines.
  • Correct wiring and control components if pumps or alarms are present; verify electrical safety and code compliance.

Real estate transfers and disclosures

  • Some counties require a septic system disclosure or a formal inspection as part of a real estate transaction; the exact requirement varies by county.
  • If you're listing or buying a home with a septic system, plan a pre-listing or pre-closing inspection to avoid delays.

Official resources

Septic Maintenance for Homes in Loganville

Loganville-specific conditions that affect your system

Loganville sits in Gwinnett County with soils that often include dense clay and a seasonal high water table. Heavy spring rains and occasional flooding can saturate drain fields, making pumping and field restoration more frequent. Mature trees common in Loganville yards send roots toward septic lines; roots can damage tanks, distribution boxes, and laterals. Because many lots are standard suburban lots with limited separation between tanks and property lines, proper maintenance and timely pumping are essential to prevent backups.

Regular maintenance schedule for Loganville homes

  • Pump your septic tank every 3-5 years for a typical family of four with a 1,000-gallon tank; smaller tanks or higher wastewater flow may require more frequent pumping. Keep pumping records in a home file.
  • Schedule an annual or biennial professional inspection to check tank baffles, outlet tees, pump chamber, distribution box, and more. In Loganville's clay soils, pay attention to field integrity and soil absorption.
  • Use water efficiently: fix leaks, install high-efficiency toilets and fixtures, and spread laundry and dishwater use across the week to reduce peak loads on the system.
  • Protect the drain field: avoid driving or heavy equipment on the area, and coordinate landscaping plans with your septic pro.

Loganville-specific challenges and practical fixes

  • Clay soils and slow absorption: consider soil amendments or a funded system evaluation if you notice standing water or soggy areas above the field; ensure the field has proper grading away from the house.
  • High water table and rainfall: in seasons of heavy rain, reduce irrigation and avoid dumping excess water into the septic tank; verify that surface runoff is directed away from the drain field.
  • Tree roots: plant root barriers or relocate landscaping away from the septic field; prune nearby trees but avoid damaging the tank or lines.
  • Odors and backups: odors in the house after rainfall or heavy use can indicate a compromised drain field; schedule an inspection promptly.

Practical maintenance steps you can take this year

  1. Locate and map your septic system: mark the tank access lids and the drain-field boundaries; keep a copy of the as-built plan.
  2. Schedule pumping with a licensed septic contractor familiar with Loganville soils; confirm the tank size, driveway access, and disposal location.
  3. Have an annual inspector check baffles, manholes, the distribution box, and any submersible pumps if present.
  4. Conserve water: install water-saving fixtures; run full loads; spread out laundry to prevent overload.
  5. Use septic-safe products and avoid flushing non-biodegradables or letting fats and oils down the drain; compost scraps instead of garbage disposals when possible.
  6. Plan yard work with care: call 811 before digging and keep heavy equipment off the field.

Signs of trouble to watch for in Loganville

  • Gurgling sounds, slow drains, sewage odors, damp spots or lush green patches over the drain field, or wastewater backups.

Resources

  • EPA: Onsite Wastewater Treatment Systems -

Cost Expectations for Septic Services in Loganville

Septic Tank Pumping

  • What this includes: removing accumulated sludge and scum from the septic tank to prevent breakdown of the system, inspecting the tank access lids, and recording the service for future maintenance. In Loganville, proximity to older tanks and drain fields means pumping is a common, essential maintenance step.
  • Loganville-specific notes: clay soils, variable water tables, and mature systems in older neighborhoods can influence how often pumping is needed and how the tank interacts with the drain field.
  • Typical cost in Loganville: $250–$500 per pump, with some jobs reaching $550–$600 if access is difficult or multiple tanks are involved.
  • Preparation tip: have the yard marked where the tank lid sits and ensure pets are kept away during pumping.

Septic System Inspections (Pre-purchase and Annual)

  • What this includes: overall system health check, tank inspection, baffle check, lid/risers if present, and a recommendation for pumping if solids are high. For Loganville real estate, inspections are a common prerequisite for closings and for ongoing home maintenance.
  • Loganville-specific notes: in real estate transactions, buyers often request a camera or dye test to confirm the drain field isn't failing, which can be more likely in older Loganville homes with clay soils.
  • Typical cost in Loganville: $150–$350 depending on whether a basic inspection or a full report with recommendations is performed.

Camera Inspection / Diagnostic

  • What this includes: video inspection of pipes from the tank to the drain field to locate cracks, roots, obstructions, or broken lines; sometimes paired with dye tests.
  • Loganville-specific notes: older or extensively landscaped properties may reveal root intrusion or buried line problems that aren't visible from the surface.
  • Typical cost in Loganville: $200–$450.

Drain Field Evaluation

  • What this includes: soil evaluation, moisture testing, and performance assessment of the absorption area to determine if the drain field is functioning as designed.
  • Loganville-specific notes: clay soils and variable moisture in parts of Loganville can mask field problems; evaluations help decide whether the field needs repair, replacement, or optimization.
  • Typical cost in Loganville: $350–$900.

Drain Field Repair

  • What this includes: pipe repairs, lateral replacements, fixing broken tees, or segmenting the drain field to restore function.
  • Loganville-specific notes: in neighborhoods with dense clay or aging fields, repairs may be more frequent and can involve additional access points or creative configurations.
  • Typical cost in Loganville: $2,000–$7,000, depending on scope; complex fixes or partial replacements can run higher.

Drain Field Replacement

  • What this includes: installing a new drain field, which may involve trenching, gravel beds, perforated piping, and soil restoration; sometimes used when the current field is no longer viable.
  • Loganville-specific notes: in older Loganville sites, a full replacement (often with a mound or alternative design) may be necessary due to soil conditions and system age.
  • Typical cost in Loganville: $6,000–$15,000 or more, influenced by field type (conventional vs. mound) and site access.

Septic System Installation (New Systems)

  • What this includes: permitting, soil testing, design of a new tank and drain field, installation, backfill, and initial start-up checks.
  • Loganville-specific notes: local permitting and soil constraints can impact design choices; mound systems are more common in areas with shallow bedrock or poor soil percolation.
  • Typical cost in Loganville: Conventional system $6,000–$10,000; mound systems $15,000–$40,000+ depending on site conditions and regulatory requirements.

Septic Tank Repair

  • What this includes: baffle repair or replacement, leak fixes, sealant work, or re-sealing manholes and access points.
  • Loganville-specific notes: small fixes are common in aging Loganville tanks; timely repair can prevent field damage.
  • Typical cost in Loganville: $200–$1,000 for minor fixes; more extensive repairs can reach $1,000–$3,000.

Pump Replacement

  • What this includes: replacing the pump or effluent pump inside the tank, wiring checks, and sometimes control switch or float replacement.
  • Loganville-specific notes: pump failures can occur in hotter months or with aging tanks; ensure proper sizing for your system.
  • Typical cost in Loganville: $1,000–$2,500.

Aerobic System Service and Maintenance

  • What this includes: routine service for aerobic or alternative systems, including pump checks, aerator maintenance, filter cleaning, and occasional parts replacement.
  • Loganville-specific notes: aerobic systems are less common than conventional tanks in older Loganville homes but are more prevalent in newer builds or specific neighborhoods; maintenance visits are typically scheduled 1–2 times per year.
  • Typical cost in Loganville: $300–$500 per service visit, with parts and filter replacements extra.

Tank Lid / Access Replacement

  • What this includes: replacement lids, risers, and seals to ensure proper access and odor control.
  • Loganville-specific notes: in areas with heavy landscaping, finding and replacing lids may require additional digging or relocation.
  • Typical cost in Loganville: $200–$700.

Preparation steps for a service visit (quick guide)

  1. Locate tank lids and mark access points.
  2. Clear the area around the lid for easy access.
  3. Note any prior pumping dates or tank issues.
  4. Make sure pets and children are away during the service.
  5. Have a copy of any past inspection reports or permits handy.

Official resources

  • Georgia Environmental Protection Division – On-Site Sewage Management:
  • Georgia Department of Public Health – On-Site Sewage Management:
  • EPA septic system information: https://www.epa.gov/septic