Septic in Brandon, SD

Last updated: Mar 21, 2026

Welcome to Brandon, SD—a friendly, growing community where tree-lined streets meet practical know-how. If you're buying or maintaining a home here, you'll notice something important about many properties: not every house sits on a city sewer line. That local pattern shapes how homes handle wastewater and why a trusted septic pro is a valuable neighbor to know.

Is septic common in Brandon? Should I expect septic if I own or buy a home?

Is septic common? Yes, especially for homes outside the municipal sewer service area or on larger lots. In neighborhoods closer to town, city sewer is more common, but outside those boundaries septic systems are a familiar part of Brandon's housing mix.
Should I expect septic? If your Brandon home isn't connected to the city sewer, you'll have a septic system. When you're buying, verify sewer status with the seller, title company, or city utility records, and ask about any recent pumping or inspections.

Why homes typically use septic systems in Brandon

Lot size and layout: Brandon's mix of urban, suburban, and rural lots means some properties have the space and soil for well-designed septic systems without compromising neighborhood character.
Infrastructure reach: Extending a municipal sewer main to every property can be slow and costly. Septic systems provide a practical, affordable wastewater solution where centralized infrastructure isn't nearby.
Cost and practicality: For many homeowners, on-site treatment is the most straightforward way to manage waste on parcels that aren't immediately served by a sewer line, especially on acreage or in developing areas.
Environmental stewardship: Properly designed and maintained septic systems help protect groundwater and local waterways, which matters in the local water systems around Brandon.

High-level explanation (why septic exists here)

In Brandon, on-site wastewater treatment became the practical standard as the town grew outward from the core. The combination of available land, soil conditions, and the cost of extending underground utilities led many property owners to rely on septic systems. When well-designed, installed, and pumped on schedule, these systems provide a reliable, long-term solution that keeps homes comfortable and the local environment healthy.

As your neighbor and septic professional, I'm here to help you understand maintenance needs, pumping intervals, and what to watch for to keep your Brandon septic system running smoothly.

Where Septic Systems Are Common in Brandon

Unsewered outskirts and rural parcels

Brandon's traditional "sewered town" core sits alongside a broad ring of unsewered land. Septic systems are most common here on:

Rural homes, farms, and larger-acre parcels where tying into municipal mains isn't feasible or cost-effective.
Properties outside the city's current sewer service area or in areas where expansion hasn't reached yet.
Older homes built before nearby sewer lines were installed or extended.

In these zones, a properly designed on-site system is essential for protecting groundwater and nearby wells. If you're buying, ask specifically about whether a septic is present and when the last pump or inspection occurred.

Areas with older neighborhoods and annexations

Not every Brandon neighborhood is connected to a sewer main today. You'll see septic more frequently in:

Older subdivisions that were built before sewer mains were extended, or before sewer connections became mandatory.
Recently annexed or transitioning areas where the city has begun assessing sewer upgrades but some properties still rely on septic temporarily.
Properties on curves of terrain where sewer access is limited or cost-prohibitive.

In these spots, septic maintenance is a routine part of homeownership, and future developments may bring mandatory sewer hookups as Brandon continues to grow.

Soil and site considerations that influence septic use

Site conditions shape where septic is practical. In Brandon, septic prevalence aligns with how soils and groundwater behave locally:

Well-drained loams and sandy caps allow efficient septic drain fields when properly sized and sited.
Clay-rich soils, high water tables, or shallow bedrock can complicate septic performance and may require specialty designs or mound systems.
Landscape features such as slopes or proximity to wells (private or community) influence setback distances and field layout.

A soil test and a professional evaluation are key to determining if a given property is suitable for on-site wastewater disposal.

Verifying whether your Brandon property uses septic or sewer

If you're unsure which system serves your property, use these steps:

Check with the City of Brandon's public works or utilities to confirm whether you're in the sewer service area.
Inspect for a sewer cleanout or a sewer lateral on the property street side and in your utility box area.
Review property records, tax statements, or recent surveys for sewer connection language.
Have a licensed septic contractor or a soil scientist evaluate the site and your system (if present).

If you're buying or selling, request a formal septic inspection as part of the transaction so you won't be surprised by required upgrades later.

Maintaining a septic system in Brandon-adjacent settings

Proactive care keeps septic systems reliable in Brandon's mix of sewered and unsewered lots. Follow these practical steps:

Pump every 3–5 years (frequency depends on household size, tank size, and wastewater volume).
Protect the drain field: avoid heavy equipment, parking, or planting trees over the system.
Use water-efficient fixtures and fix leaks promptly to minimize tank loads.
Be mindful of what goes into the system: fats, oils, fuels, solvents, harsh cleaners, and non-degradable items can clog or kill beneficial bacteria.
Schedule periodic inspections by a licensed septic professional to catch early issues before failures.

Official resources you can consult

South Dakota DENR: Onsite Wastewater Systems guidance and regulations (official state resources) —
South Dakota State University Extension: Homeowner guidance on septic systems and best practices — https://extension.sdstate.edu
U.S. Environmental Protection Agency: Septic systems overview and consumer tips — https://www.epa.gov/septic

Septic vs Sewer: What Homeowners in Brandon Should Know

How the systems differ

Public sewer: Your home connects to a municipal sewer system; wastewater goes through shared pipes to a city or district treatment plant. You typically pay a monthly sewer bill to the local utility.
Private septic: Your own underground system on your property treats and disperses wastewater on site. You're responsible for pumping, inspection, and eventual replacement, if needed.

Key idea: sewer systems handle wastewater for many homes, while septic systems handle it on one property. The maintenance mindset and costs differ accordingly.

Local reality for Brandon homeowners

In Brandon, SD, some homes are connected to city sewer, while others rely on private septic systems. Check your property records, tax bill, or ask the Brandon municipal utility or Minnehaha County for confirmation.
If you're on sewer, expect ongoing monthly charges and fewer on-site maintenance tasks. If you're on a septic system, you'll manage pumping, inspections, and drain-field care to protect soil and groundwater.

Costs and maintenance at a glance

Sewer-connected homes:
- Regular monthly service charges set by the city or district.
- Fewer on-site maintenance tasks, but be mindful of sewer line blockages that can cause backups.
Septic system homes:
- Installation requires a larger upfront investment (systems vary by lot and soil).
- Routine pumping every 3–5 years is common; inspections every 1–3 years help catch issues early.
- Drain-field replacement or repairs can be costly but are less frequent with good maintenance.
- Ongoing maintenance tasks keep your system functioning for decades.

Maintenance best practices

Use water efficiently: spread out laundry and dishwashing, fix leaks promptly, and consider high-efficiency appliances.
Protect the drain field: avoid parking or placing heavy structures over the drain field; plant only shallow-rooted grasses nearby; keep trees away to prevent root intrusion.
Be mindful of what goes down the drain: no grease or油, flushable wipes, or harsh chemicals that can kill beneficial bacteria in the tank.
Routine checks: have the tank inspected and pumped on schedule if you have a septic system; monitor for signs of trouble like gurgling sounds, slow drains, or bright green, soggy patches in the yard.

Steps to take if something goes wrong

Stop using water-intensive appliances temporarily to reduce load on the system.
For septic systems, call a licensed septic professional to assess and pump if needed.
If you're on municipal sewer and notice backups or abnormal sewer odors, contact the Brandon city utility or your local public works department.
Document dates of inspections, pumping, and any repairs for future reference.
Consider a preventive maintenance plan with a local provider to extend system life and protect your property value.

Official resources

EPA Septic Systems:
South Dakota Department of Health: https://doh.sd.gov

Typical Septic System Types in Brandon

Conventional gravity septic system

Most Brandon homes rely on a conventional gravity system: a buried septic tank connected by gravity to a drainfield. Solids settle in the tank while liquids exit to the soil absorption area through gravity. This setup works well when soils are suitable, the groundwater table is reasonably deep, and there's adequate space for a drainfield.

Components: septic tank (typical sizes range with home load, often 1,000–1,500 gallons), distribution box, perforated pipes, and a drainfield trench or bed.
Pros: simple, low up-front cost, easy to maintain with periodic pumping.
Cons: performance drops with high water tables, shallow soils, or poor percolation; requires sufficient lot area.
Maintenance note: have the tank pumped every 3–5 years (size and usage change the interval); protect the drainfield from heavy vehicles and deep digging invasions.

Mound systems

When Brandon soils are shallow, have a high water table, or poor percolation, a mound system is installed. The drainfield is built above the native soil on a raised mound that provides better treatment through the built sand layer.

When used: restrictive soils, groundwater proximity, or limited space for a traditional drainfield.
Pros: expands workable sites for septic systems; reliable in challenging soils.
Cons: higher initial cost; requires power for dosing if used; more maintenance components.
Maintenance: regular inspections, follow pumping schedules for pretreatment tanks, watch for signs of surface seepage or damp areas.

Pressure-dosed (pressure distribution) systems

In soils with variable absorption, a pressure-dosed system uses a small pump to distribute effluent evenly across multiple trenches. This prevents overloading any single trench and improves performance.

How it works: a pump, control panel, and timed dosing cycles feed effluent into several trenches.
Pros: more uniform distribution, better performance in inconsistent soils.
Cons: more components to service; electricity is essential.
Maintenance: keep the pump and control components accessible; annual system check by a qualified contractor.

Aerobic Treatment Units (ATUs)

ATUs provide enhanced treatment before the drainfield and are common where soil conditions are marginal or space is limited. They require electricity and regular professional maintenance to keep effluent quality high.

What they do: biologically treat wastewater to a higher standard than a conventional system.
Pros: smaller or less-dense drainfields; improved effluent quality in poorer soils.
Cons: higher ongoing maintenance and energy costs; model and component replacements may be needed over time.
Maintenance steps: service every 6–12 months, keep records, use only manufacturer-approved cleaners and parts.

Sand filter systems

A sand filter system uses a pretreatment tank and a sand-based filtration layer before the effluent enters the drainfield. This can help where native soils do not provide sufficient treatment.

Components: pretreatment tank, sand filtration bed, distribution network.
Pros: additional treatment step can extend drainfield life in restrictive soils.
Cons: larger footprint and ongoing maintenance of the filter media.
Maintenance: periodic inspection of the filtration media and replacement as recommended by the installer.

Drip irrigation and evapotranspiration (ET) beds

These options are less common in Brandon but may be used in landscape-focused designs or lots with limited drainfield space. Drip irrigation transports treated wastewater to the root zone; ET beds rely on plants and sun/water loss to move water away.

Suitability: requires careful design, permitting, and ongoing monitoring.
Pros: potential landscape integration and water-use efficiency.
Cons: specialized design, higher maintenance, and local code considerations.

How to choose the right system for your Brandon home

Get a site evaluation from a licensed onsite wastewater designer or engineer to assess soil, groundwater, and lot features.
Review local codes and permitting requirements with the Brandon city or county authority, and consult state guidance from the appropriate agency.
Compare maintenance needs, long-term costs, and energy requirements across options (especially if considering ATUs or mound systems).
Obtain multiple quotes from qualified installers and verify maintenance contracts before proceeding.

Resource links:

EPA Septic Systems:

Common Septic Issues in Brandon

Drain Field Saturation and Failure

Brandon sits on soils that can be clay-heavy with a higher seasonal water table. In wet springs and after heavy rains, the drain field can become saturated, slowing or stopping water dispersal and causing odors or surface pooling.

Symptoms: slow drains, gurgling sounds in the plumbing, soggy or spongy areas above the drain field, and occasional sewage smells in the yard.
Brandon-specific risks: clay soils and spring melt increase field saturation; nearby drainage patterns and higher groundwater can limit infiltration.
What to do:
1. Limit water use and avoid irrigation until the field dries.
2. Have a licensed septic professional pump and inspect the tank.
3. If saturation persists, evaluate alternative designs (mound systems or other dispersal methods) designed for clay soils.
4. Remove trees or heavy roots within about 20 feet of the field to reduce uptake of moisture and root intrusion.
When to seek help urgently: you notice sewage backing into fixtures or active surface odors after a rainstorm.

Tank and Baffle Problems

A cracked tank, damaged outlet baffle, or failing connections can push solids into the drain field, speeding field failure and causing backups.

Symptoms: backups in toilets or sinks, strong sewage odors inside the home, standing water or sludge at the septic tank access.
Brandon-specific risks: many older Brandon homes may have older tanks or original baffles that have degraded.
What to do:
1. Have a licensed plumber or septic pro inspect the tank and outlet baffles.
2. Pump the tank to remove accumulated sludge and scum.
3. Replace faulty baffles or the tank if damage is present.
4. After repair, schedule regular inspections every 1–3 years and pumping per local guidance.
Quick prevention: address issues early to avoid costly drain-field damage.

Freezing and Seasonal Impacts

Brandon's cold winters can freeze shallow lines or access components, slowing effluent flow and creating backups during the coldest months.

Symptoms: slow drainage in winter, toilets flushing slowly, frost or ice near access ports.
Brandon-specific risks: shallow trenches, inadequate insulation, and gear left uncovered can magnify freeze risks.
What to do:
1. Ensure proper insulation around tanks and exposed piping; keep venting clear.
2. Do not park on or drive over the drain field in winter.
3. If freezing is persistent, consult a professional about frost-protected designs or rerouting lines.
4. Maintain a stable, moderate temperature around the system and avoid rapid temperature swings.
When to seek help: if you notice repeated freezing-related backups or damage to lids and covers.

Water Use and Household Management

Excessive water use or improper disposal can overwhelm the system, especially in smaller Brandon lots and older installations.

Symptoms: slow drains, backups after showers/laundry, damp spots that worsen with rain.
Brandon-specific risks: older homes may lack modern high-efficiency fixtures; irrigation and high-volume loads stress the system.
What to do:
1. Do a home water-use audit and fix leaks.
2. Install low-flow fixtures and energy-efficient appliances.
3. Stagger laundry and dishwasher loads; avoid long runs of water after pumping.
4. Limit non-sewage discharges (excess grease, fats, and certain chemicals) from entering the tank.
Quick win: keep daily wastewater loads within the system's design capacity.

Root Intrusion and Landscaping

Tree roots and aggressive plantings near the drain field can invade pipes and reduce infiltrative capacity.

Symptoms: persistent slow drainage, biofilm buildup, and cracks or upheaval in nearby soil.
Brandon-specific risks: mature trees in older subdivisions increase root intrusion risk.
What to do:
1. Locate and assess the drain field and pipelines with a trained professional.
2. Prune or remove problematic trees/roots near the field, or install barriers.
3. Re-landscape with setback plans that keep plantings away from the drain field.
Prevention: plan landscaping with a safe clearance zone around the field.

Flushing Non-Biodegradable Items

Disposing wipes, diapers, sanitary products, or household chemicals into the system disrupts operations and can clog the tank or pipes.

Symptoms: frequent clogs, backups, and odor issues.
What to do:
1. Enforce a no-flush rule; only toilet paper goes down the toilet.
2. Use septic-safe products and proper waste disposal for chemicals.
3. Consider installing a coarse screen at the tank inlet to catch large items.
If problems persist, arrange a professional inspection.

Resources:

EPA:
SDSU Extension (Septic systems resources): https://extension.sdstate.edu

Septic Inspection, Permits & Local Oversight

Local oversight in Brandon

Brandon operates with a mix of city and county oversight. Within city limits, the City of Brandon Building Department typically handles septic-related permits and required inspections. In rural or unincorporated areas of Brandon, Minnehaha County environmental health staff often oversee onsite wastewater systems.
The state-level standards come from the South Dakota Department of Environment and Natural Resources (DENR) Onsite Wastewater Treatment Systems (OWTS) program, which sets technical rules and coordinates with local authorities.
Always confirm jurisdiction before starting work. Start with the City of Brandon Building Department if you're in town, or contact Minnehaha County Environmental Health for rural areas. You can also refer to the state OWTS guidance for the statewide framework:

Do I need a permit?

In most Brandon projects, installing, modifying, repairing, or abandoning an onsite septic system requires a permit.
If you're connected to municipal sewer, a septic permit may not be needed, but you'll still need to confirm with the local authority.
Even small repairs or routine upgrades can trigger permitting or inspection requirements, depending on jurisdiction and the scope of work.
Always check early with the local building or health department to avoid delays or violations.

How to determine the rightPermitting path

Contact the local authority:
- City of Brandon Building Department for within-city work.
- Minnehaha County Environmental Health for rural or county areas.
Ask which agency issues the permit, what forms are required, and what designs are acceptable.
Gather initial information:
- Property deed and legal description
- Proposed site plan (lot boundaries, structure placement)
- Soil/groundwater considerations or a soil evaluation if available
- Preliminary system design or a licensed designer's plan
Confirm whether state-level DENR approval or review is needed in addition to local permits.
Submit the application with all supporting documents and pay any applicable fees.

Steps to apply for a permit

Prepare a complete application package with site plans, a certified septic designer's plan, and any soil eval logs.
Submit to the appropriate agency (city building department or county health/environmental health) as directed.
Await plan review and any required revisions.
Receive permit approval and schedule inspections.

Inspections you'll encounter

Pre-installation inspection: confirm site suitability, setback compliance, and access for equipment.
In-progress inspections: review sewer trenching, piping, tank placement, baffle orientation, and soil absorption area installation.
Final inspection: verify system operation, water testing where required, proper cover materials, and documentation.
Keep records: save inspection reports, approved plans, and any warranty or maintenance documentation for future property transfers.

What to have ready when inspecting

Final approved septic design and permit number
Itemized bill of materials and contractor information
As-built drawings or final layout if different from the submitted plan
Any required backfill or cover materials documentation

Understanding the timeline

Permit reviews can take days to several weeks, depending on jurisdiction and workload.
Inspections are scheduled around construction progress. Delays often arise from incomplete submissions or missing documentation.
Plan for weather-related delays if soil conditions or access are impacted.

Resources you'll find helpful

South Dakota DENR Onsite Wastewater Treatment Systems:
If you're outside Brandon city limits, check with Minnehaha County Environmental Health for county-specific guidance and contact options:
State guidance and standards can help interpret local actions and expectations during planning and review.

Septic Maintenance for Homes in Brandon

Brandon-specific factors to know

Brandon's cold winters, spring thaws, and a mix of soils common in the Brandon area can affect how quickly your septic system drains and how often you need to pump. In clay-heavy soils, absorption can be slower, so the drain field needs a bit more protection from heavy use and compaction. Keep in mind that saturated soil from snowmelt and rain can stress a drain field, especially if roof and surface drainage flow toward it.

How often to pump and tank sizing

Typical residential septic tanks are 1,000 to 1,500 gallons.
A common starting point for a family of four in Brandon is pumping every 3 years; larger families or heavy use (garbage disposals, in-home businesses) may require every 2 years.
If the sludge layer reaches one-third of the tank depth or more, schedule pumping promptly. A professional should verify sludge and scum levels during an inspection.

Seasonal maintenance plan (step-by-step)

Spring (after snowmelt): Have a professional inspect the tank and drain field for signs of saturation or standing water; schedule pumping if solids are high.
Summer: Conserve water to reduce load; avoid heavy irrigation near the drain field; use low-flow fixtures.
Fall: Prepare for freezing temps by ensuring the area around the tank and drain field is clear and protected from compaction; direct downspouts away from the field.
Winter: Keep access lids clear of snow; avoid driving or parking on the drain field; short, warm-water flushes help keep the system active without overloading it.

Drain field protection in Brandon

Avoid heavy vehicles or equipment on the drain field; it's easy to compact soils in winter and spring.
Do not plant trees or deep-rooted shrubs near the drain field; grasses or low-growing ornamentals are best.
Direct roof and surface runoff away from the drain field to prevent over-saturation.

Water-use habits and disposals that help

Fix leaks promptly; even small drips waste considerable water over a year.
Use water-efficient fixtures (low-flow toilets, showerheads, washers).
Limit garbage disposals; consider composting organic waste.
Never flush non-biodegradable items, solvents, fuels, or chemicals; these harm beneficial bacteria.

Signs of trouble and what to do

Slow drains, gurgling sounds, sewage odors, damp spots above the drain field, or brightly green, lush patches can indicate trouble.
If you notice problems, contact a licensed septic professional promptly. Do not pump or pressure-clean yourself; this can worsen issues.

Find a Brandon-area septic professional

Look for licensed septic installers in the SD DENR Onsite Wastewater Systems directory and verify their credentials.
Ask for references, recent inspections, and a written plan before work begins.

Helpful resources

Onsite Wastewater (South Dakota DENR):
EPA Septic Systems:

Cost Expectations for Septic Services in Brandon

Septic Tank Pumping and Cleaning

What it includes: pumping out settled sludge and scum, measuring tank levels, inspecting baffles and inlet/outlet pipes, and recording tank condition. If a riser or lid needs installation for easier future access, that may be quoted separately.
Brandon-specific notes: many Brandon homes use 1,000–1,500 gallon tanks; larger or multi-compartment tanks change the price. Winter access can add a bit to the cost if driveways or tanks are blocked by snow.
Typical cost in Brandon: $250–$600, depending on tank size and accessibility.
Preparation steps (numbered):
1. Locate and mark the tank access lids.
2. Clear a path to the lids if possible.
3. Remove vehicles from the work area to allow equipment access.

Septic System Inspection

What it includes: visual inspection of the tank, risers, lids, and access points; drain-field evaluation; functional tests of pumps and alarms; dye tests or camera inspection if warranted.
Brandon-specific notes: a full assessment helps catch early drain-field issues common after droughts or heavy rains in the region; expect additional cost for camera inspections if a problem is suspected.
Typical cost in Brandon: basic inspection $100–$200; full inspection with advanced tests $250–$500.
Helpful tip: ask for a written report with recommendations and repair priorities.

Routine Maintenance / Service Contracts

What it includes: scheduled pumping, annual inspections, priority scheduling for repairs, and discounted rates on repairs or parts.
Brandon-specific notes: local contractors frequently offer annual plans to keep systems compliant with state guidelines and to extend tank life.
Typical cost in Brandon: $150–$300 per year, depending on tank size and service frequency.

Septic System Installation (New System)

What it includes: site evaluation, design, permit coordination, trenching or mound installation, tank and drain-field setup, soil testing, and startup checks.
Brandon-specific notes: soil and groundwater conditions around Brandon can influence whether a conventional system or mound system is required; permit processes through SD DENR apply.
Typical cost in Brandon: $3,000–$8,000 for conventional systems; $10,000–$25,000+ for mound or advanced systems.
Preparation steps (numbered):
1. Confirm lot setbacks and soil suitability.
2. Obtain necessary permits and timeframes.
3. Plan for a drainage path and future maintenance access.

Drain Field Repair or Replacement

What it includes: locating damaged trenches or pipes, repairing or replacing distribution lines, replacing gravel or soil as needed, and re-testing performance.
Brandon-specific notes: drain-field performance in clay-heavy soils or shallow bedrock areas common to parts of the region may require tailored remediation.
Typical cost in Brandon: $2,000–$10,000 for repair; $5,000–$25,000+ for full replacement.
Quick reference: a failing field is often less expensive to address early than waiting for complete failure.

Drain Field Jetting and Root Removal

What it includes: high-pressure water jetting of lines, root cutting, and clearing obstructions; follow-up inspection to confirm flow.
Brandon-specific notes: root intrusion from trees or shrubs near the drain field is a frequent issue in newer Brandon neighborhoods.
Typical cost in Brandon: $150–$400 per hour or $500–$1,000 per job, depending on access and diameter of lines.

Pump or Control Panel Service

What it includes: inspection of pumps, floats, alarms, and electrical connections; replacement of failed components when needed.
Brandon-specific notes: lift stations or grinder pumps are less common in older rural layouts but can appear with newer developments; verify power supply and warranty options.
Typical cost in Brandon: $150–$400, plus parts if replacements are required.

Tank Risers, Lids, and Access Maintenance

What it includes: installation or replacement of risers and secure, accessible lids to simplify future pumping.
Brandon-specific notes: rising to grade level reduces future labor and cost, particularly in snowy winters.
Typical cost in Brandon: $500–$1,500.

Filtration / Effluent Filter Cleaning

What it includes: cleaning or replacing the effluent filter, inspecting the baffle integrity, and confirming proper flow to the drain field.
Brandon-specific notes: replacing a clogged filter can prevent premature drain-field stress.
Typical cost in Brandon: $100–$300.

Septic System Abandonment / Decommissioning

What it includes: safely sealing and filling the tank, disconnecting and capping lines, and documenting decommissioning for future property sales.
Brandon-specific notes: required if you'll be selling the property or converting to a non-septic system.
Typical cost in Brandon: $500–$3,000, depending on tank size and site access.

Emergency Septic Service

What it includes: 24/7 response to backups, overflows, or alarms, with rapid assessment and triage.
Brandon-specific notes: after-hours service may carry a higher hourly rate or trip charge.
Typical cost in Brandon: $150–$350 call-out plus any parts or repairs needed.

Official resources and guidance:

EPA Septic Systems:
General guidance for homeowners and code compliance: https://www.epa.gov/septic or state-specific pages linked above