Septic in Brownsville, OR

Welcome to Brownsville, where old-town charm and open hillside spaces meet a close-knit community feel. If you've ever driven past a quiet side street and noticed a neatly buried tank or a gently sloped drain field, you're seeing what makes Brownsville homey and functional for many residents. For homeowners and those considering a purchase, practical, trustworthy guidance on septic systems is part of keeping this town's water-safe and land-friendly character.

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

• Yes. Septic systems are common in Brownsville and the surrounding areas where centralized sewer service isn't on every street or property line. Many homes operate on their own on-site systems, and you'll still find a good mix of properties that are connected to a municipal sewer when that option is available.
• If you're buying a home here, expect to encounter a septic system on many properties or to confirm there's a sewer connection where relevant. Always verify with the seller, the realtor, or the local public works or sewer district about current service and any maintenance records.

Why homes typically use septic systems in Brownsville

• The layout and history of the area mean many properties sit on larger lots with private underground plumbing needs. Extending mains through hillside streets and farmland isn't always practical or cost-effective, so on-site solutions have become the norm.
• Local development patterns favored individual septic setups for decades, especially outside newer subdivisions, rural-adjacent neighborhoods, and areas where a city sewer line hasn't reached every parcel.
• A septic system keeps wastewater treatment close to home, reduces the need for long sewer mains, and works well when properly designed for the soil and landscape you're building on.

High-level explanation (why septic exists here)

• Septic systems use a tank to separate solids from liquids, with the clarified liquid treated by a drain field in the soil. In Brownsville, this on-site approach is practical because it aligns with the terrain, soil conditions, and the cost profile of extending centralized services to every parcel. When properly installed and maintained, a septic system helps protect local groundwater and supports the town's rural-meets-town character.

If you're ready to dive deeper, you'll find practical, neighborly guidance on inspection, maintenance, and common concerns right here as you explore the Brownsville page.

Where Septic Systems Are Common in Brownsville

Core Brownsville: where septic is most common

In Brownsville, you'll encounter septic systems most often in the older residential districts and in properties that sit outside the town's municipal sewer lines. Many homes built before sewer extensions reached them relied on on-site wastewater treatment from the start, and some newer builds in the same areas continue to use septic as a practical, cost-effective option. If your property is inside or near the city limits but not connected to a centralized sewer, septic is a common choice.

• Expect standard gravity-fed septic setups on smaller lots.
• In pockets with limited sewer coverage, alternatives like mound or advanced treatment units show up more frequently.

Rural outskirts and larger lots

Outlying parcels and rural properties around Brownsville are even more likely to use septic systems. The combination of larger lot sizes and the absence of continuous sewer service makes on-site systems the practical approach for waste disposal. You'll see a mix of traditional drainfields on well-drained soils and, where soils or groundwater conditions aren't ideal, engineered designs such as mound systems or ATUs (advanced treatment units).

• Larger lots make it easier to accommodate drainfields with adequate setback distances.
• In water-table-prone or clay-heavy areas, you may notice more engineered solutions to meet local code and performance goals.

Soil, water, and design: why Brownsville shapes septic choices

Brownsville sits in the Willamette Valley with soils that vary from fine, loamy textures to heavier clays. Soil drainage, depth to groundwater, and seasonal water table fluctuations all influence septic design. Areas with permeable soils and stable drainage favor conventional drainfields, while zones with shallow groundwater or poor infiltration require alternatives like mound systems or pressure-dosed fields.

• Proper siting matters: avoid high-traffic zones, foundations, and wells when locating a septic system.
• Seasonal water table changes can impact how quickly a field drains and ionizes effluent.

Common septic system types you'll see in Brownsville

• Gravity systems: The traditional setup with a septic tank and a drainfield that relies on natural gravity to distribute effluent.
• Mound systems: Elevated drainfields used on sites with shallow soil, high water tables, or poor drainage.
• Advanced treatment units (ATUs): Small, self-contained systems that pre-treat wastewater before it enters the drainfield, useful on marginal soils.
• Drip or spray irrigation enhancements: In some landscaped or rural properties, treated effluent is distributed via controlled irrigation methods (where permitted).

Maintenance and best practices

• Pumping: Most residential systems benefit from pumping every 3–5 years, depending on usage, tank size, and local conditions. Heavier use or older systems may need more frequent service.
• Protect the drainfield: Keep vehicles and heavy equipment off the drainfield area; avoid planting trees or shrubs with aggressive roots nearby.
• Water use: Spread out loads of water across the day; fix leaks promptly to reduce continuous loading on the system.
• Septic-safe practices: Use products labeled safe for septic systems and minimize solids entering the tank (garbage disposals, fats, and non-biodegradable items can clog or overwhelm the tank).

Quick reference steps for Brownsville homeowners

1. Locate your system and pull the permit or installation records from the local or state authority.
2. Hire a licensed septic professional to inspect the tank and drainfield—especially before buying or if you notice odors, pooling, or slow drains.
3. Develop a pumping and maintenance schedule based on your system type and household usage.
4. Plan for possible upgrades if you're expanding the home or landscaping; consult a pro about whether a mound or ATU is appropriate for your site.

Resources

• Oregon Department of Environmental Quality (DEQ) – On-Site Wastewater Program:
• U.S. Environmental Protection Agency (EPA) – Septic Systems: https://www.epa.gov/septic

Septic vs Sewer: What Homeowners in Brownsville Should Know

How sewer and septic service differ in Brownsville

• Municipal sewer systems collect wastewater from homes and businesses and carry it to a centralized treatment facility. If you're connected, your daily wastewater is treated offsite.
• A septic system is an on-site solution: wastewater goes into a tank on your property, where solids settle, liquids move to a drainfield, and soils provide final treatment.
• Not every property in Brownsville has sewer service. Availability depends on local infrastructure, zoning, and your address. Check with your city or county to confirm connections.
• Ownership and responsibility differ: with sewer, the utility maintains the main lines and treatment plant; with septic, you own and maintain the system, including pumping and repairs.

How Brownsville-specific factors affect septic performance

• Soil and groundwater: the soil type, drainage, and seasonal water table influence how well a drainfield can absorb effluent. Brownsville's soils vary, so a site-specific assessment is essential.
• Slope and drainage: steep lots or areas prone to surface water can affect how effluent disperses and how the drainfield fares over time.
• Local regulations: Oregon has rules for installing, maintaining, and abandoning OWTS (onsite wastewater treatment systems). Compliance helps protect your health and groundwater.
• A professional evaluation is your best starting point. A licensed installer or septic designer will test soil per state guidelines and determine if a conventional drainfield, mound system, or alternative design is needed for your lot.

Pros and cons at a glance

• Septic systems (on-site) pros:
  • Independence from sewer outages or rate changes.
  • Potentially lower long-term costs if well maintained.
  • Can be a good fit for rural or low-density properties.
• Septic systems cons:
  • Regular pumping and maintenance required (typically every 3–5 years, depending on use and local codes).
  • Design, installation, and repair costs are upfront and can be significant.
  • Poor maintenance can cause backups, odors, and environmental damage.
• Sewer connections pros:
  • Generally lower maintenance burden on homeowners; the utility handles treatment.
  • No tank pumping or drainfield concerns on your property (beyond occasional lateral inspections by the utility).
  • Predictable monthly charges with ongoing system reliability.
• Sewer connections cons:
  • Ongoing utility fees, sometimes subject to rate increases.
  • If a sewer main or laterals fail, repairs can disrupt multiple homes and be costly.
  • You're tied to the service area and its schedules.

Connecting to sewer vs keeping septic: a practical decision guide

1. Confirm availability: contact Brownsville city services or Linn County to see if sewer is accessible at your property.
2. Assess your current system: have a licensed septic professional inspect the tank, pipes, and drainfield for function and potential failure risks.
3. Compare costs: estimate ongoing sewer bills vs. anticipated pumping, repairs, and eventual replacement costs for your septic.
4. Consider property value and environmental risk: a well-maintained septic that's properly documented can support value, while a failing system can pose environmental and legal risks.

Maintenance basics to protect your system

• Schedule regular inspections (every 3–5 years for conventional systems; more often for complex designs) and pump when required.
• Conserve water: spread out usage, fix leaks, and install water-saving fixtures to reduce load on the system.
• Mind what goes into the drain: dispose of fats, oils, grease, chemicals, solvents, and non-biodegradable products in the trash, not the tank.
• Protect the drainfield: avoid heavy machinery, deep-rooted plants, and compaction over the absorption area; keep runoff away.
• Keep records: maintain pump dates, tank sizes, and system repairs to guide future maintenance and resale.

What to do when buying a home with septic

1. Request a current septic assessment and as-built drawings if available.
2. Check pumping history and appraisals or permits related to the OWTS.
3. Have a contingency plan for potential repairs or upgrades, and verify any required local permits for future work.
4. Consider a future severance or conversion plan if sewer service becomes available in your area.

Official resources

• — Oregon DEQ Onsite Wastewater Treatment Systems program and standards.

Typical Septic System Types in Brownsville

Conventional gravity septic system

• How it works: Septic tank collects wastewater; clarified liquid flows by gravity to a soil absorption field (drainfield) for final treatment in the soil.
• Typical components: septic tank, distribution/flow to perforated pipes, drainfield trenches, gravel, soil cover.
• Pros: Simple, solid track record; relatively low operating energy; straightforward maintenance.
• Cons: Requires sufficiently permeable soil and adequate drainage; performance can drop with high groundwater, clay, or compacted soil.
• Maintenance notes: Have the tank pumped every 3–5 years on a typical family system; inspect baffles and access lids; protect the drainfield from heavy equipment and drainage from roofs or sump pumps. For local rules and sizing, see the Oregon DEQ Onsite Wastewater Program and related guidance:

Low-pressure dosing / pressure distribution system

• How it works: A pump delivers small, evenly distributed doses of effluent to multiple drainfield lines, which helps when the soil is less uniform or the drainfield is long.
• Pros: More uniform distribution; can extend life of marginal soils; reduces wetting of the entire field at once.
• Cons: More components to service (pump, control panel); higher initial cost.
• Maintenance notes: Regularly service the pump and control units; keep a written maintenance schedule with your contractor. For regulatory context, consult Oregon's onsite wastewater resources:
• Hire a licensed septic designer/contractor familiar with Brownsville conditions and DEQ guidance. For general best practices and federal context, see EPA: https://www.epa.gov/septic

Common Septic Issues in Brownsville

Wet seasons and high groundwater

Brownsville's winter rains and the area's shallow groundwater can saturate the drainfield, making it hard for effluent to soak in. When the soil stays wet, solids and bacteria linger, and backups become more likely.

• Signs to watch: slow drains, gurgling toilets, sewage odors near the system, pooling water or soggy ground over the drainfield.
• What to do now:
  1. Conserve water during wet months (stagger laundry, avoid long showers, fix leaks).
  2. Minimize irrigation over or near the drainfield.
  3. If you notice pooling or strong odors, contact a licensed septic professional for an evaluation.
• When to call a pro: persistent damp spots, repeated backups, or changes in lawn vegetation above the drainfield.

Clay soils and slow drainage

Soils in and around Brownsville can be heavy clay, which drains slowly. Poor infiltration means effluent sits in the drainfield longer, increasing the risk of odors and system failure.

• Impact: reduced absorption, increased soil saturation after rains, sooner deterioration of the drainfield.
• Mitigation steps:
  • Have a professional test soil infiltration rates and assess drainage capacity.
  • Consider alternative designs or upgrades (mound systems, advanced treatment units, or additional treatment beds) if the soil can't support a conventional drainfield.
  • Avoid compacting the soil near the drainfield (foot traffic, heavy equipment, or outdoor storage).
• Pro tip: routine maintenance and timely upgrades often prevent full drainfield failure in clay soils.

Tree roots and landscaping near the drainfield

Tree roots and aggressive shrubs can invade drain lines and blocks of soil around the drainfield, especially in Brownsville's leafy, residential lots.

• Common symptoms: damp, lush patches above the drainfield, unexplained puddles, or slow draining indoors.
• What homeowners can do:
  • Plant new vegetation away from the drainfield and install root barriers when planting near the system.
  • Keep mature trees and large shrubs a safe distance from the drainfield; consult a professional for exact distances.
  • If roots are suspected, have the lines inspected and, if needed, clear roots with a qualified contractor.
• Maintenance note: routine inspection helps identify root intrusion before costly repairs are needed.

Drainfield aging and mis-sizing

Many older Brownsville homes rely on drainfields that have aged or were undersized for current usage.

• Symptoms: surface dampness, foul odors, toilets and sinks responding slowly, or repeated backups.
• Actions:
  • Schedule an OWTS inspection to evaluate current load, tank condition, and drainfield health.
  • Pump the tank if solids have accumulated to the point of restricting flow (as recommended by a licensed pro).
  • Discuss replacement or redesign options with a qualified installer if the drainfield is deteriorating or undersized.
• Why it's common here: older properties, combined with modern water use, can push an aging system beyond its original capacity.

Flushing and waste disposal habits

Non-biodegradable items, fats, oils, greases, and "flushable" wipes harm septic bacteria and clog lines, especially when the system is already stressed by wet soils or clay.

• Safe practices:
  • Only flush toilet paper; avoid wipes, tampons, diapers, dental floss, and cooking oils.
  • Recycle or dispose of chemicals, paints, solvents, and medications at proper facilities.
  • Use septic-safe products and limit antibacterial cleaners that kill beneficial bacteria in the tank.
• Quick checklist: station a waste disposal routine, keep a spare trash can for non-flushables, and educate all household members.

Water usage and leaks

High water use or leaks can overwhelm a drainfield, particularly when soils are slow to drain.

• What to do:
  • Fix leaks promptly; install water-efficient fixtures (low-flow toilets, high-efficiency washers).
  • Spread laundry and dishwashing across days to avoid peak loads.
  • Monitor for hidden leaks (water meter tests can help identify unseen drains).
• Step-by-step action if you suspect overuse: document symptoms, reduce water usage, call a pro for a full system evaluation, and implement recommended repairs.

Maintenance basics and pumping intervals

Routine maintenance is essential in Brownsville's climate and soil conditions.

• General guidance:
  • Most households pump every 3–5 years, but interval depends on tank size, number of occupants, and actual usage.
  • Have inspections done by licensed OWTS professionals to catch issues before they escalate.
  • Keep records of pumping, inspections, and any repairs for future service.

Resources:

• Oregon Department of Environmental Quality (DEQ) Onsite Wastewater Treatment Systems:
• EPA Septic Systems: https://www.epa.gov/septic

Septic Inspection, Permits & Local Oversight

Permits for Septic Work in Brownsville, OR

In Brownsville (Linn County), most onsite wastewater work requires a permit. That permit is typically issued by Linn County Public Health Environmental Health or the county building department, and it must align with Oregon DEQ rules for onsite systems. You need a permit for installation, replacement, or substantial modification of an OWTS.

• What the permit covers:
  • Plan review for soil suitability, system design, and setback compliance
  • Inspections at key milestones
  • Final approval before system can be activated
• What you'll typically need to apply:
  • Property address and parcel number
  • Site plan showing property lines, wells, streams, and setbacks
  • Soil evaluation/perc test results
  • OWTS design prepared by a licensed wastewater designer or civil engineer
  • Installer information and project timeline
  • Any local zoning or land-use approvals (if applicable)
  • Applicable permit fees
• Where to apply:
  • Linn County Public Health Environmental Health (onsite wastewater program):
  • Also check with Brownsville city or Linn County Building Permits office for any local forms

Inspection Process

Inspections happen at defined milestones to verify installation matches the permit and design.

• Typical milestones:
  1. Pre-construction site evaluation (if required)
  2. Trenching and pipe installation
  3. Backfill, lid installation, and final connections
  4. Final inspection and system activation
• What inspectors look for:
  • Correct placement of tanks, conduits, and distribution components
  • Proper pipe slope, backfill material, and compaction
  • Correct setbacks from wells, streams, and property lines
  • Watertight seals and lid/risers
  • Compliance with the approved design and permit conditions
• How to prepare:
  • Keep access clear; schedule in advance; have all paperwork ready
  • Address inspector notes promptly to avoid re-inspection delays

Local Oversight Bodies and Roles

• State oversight: Oregon Department of Environmental Quality (DEQ) Onsite Wastewater Program
• Local oversight: Linn County Public Health Environmental Health; Brownsville city or Linn County Building Permits as applicable
• Roles:
  • DEQ sets statewide rules and licensure
  • Local health department enforces onsite rules and issues permits
  • Local building or permit offices handle scheduling and oversight of installations
• Quick links to official sources:
  • Oregon DEQ Onsite Wastewater Program:
  • Linn County Public Health Environmental Health: https://www.co.linn.or.us/publichealth/

Practical Timeline & Tips

• Typical timeline: a few weeks to several months, depending on scope and workload.
• Pro tips:
  • Start with a preliminary plan review before soil testing
  • Use a licensed designer and installer
  • Confirm inspection dates with the right agency early

Resources & Contacts

• Oregon DEQ Onsite Wastewater Program: https://www.oregon.gov/deq/programs/land/onsite-wastewater/Pages/index.aspx
• Linn County Public Health Environmental Health: https://www.co.linn.or.us/publichealth/

Septic Maintenance for Homes in Brownsville

Brownsville climate and soil realities

Brownsville's winter rains and a tendency toward clayey, slowly draining soils can push the drainfield toward saturation in wet months. A high seasonal water table in late winter and early spring increases the risk of effluent backing up or surfacing if the system isn't well cared for. In areas where soils are heavier or the groundwater is closer to the surface, it's especially important to pace water use and protect the drainfield from compaction and root intrusion.

Pumping and tank maintenance

Regular pumping is the backbone of a healthy septic system. The rate depends on tank size, household water use, and whether you have a garbage disposal.

• Typical guidance: a 1,000–1,500 gallon tank for a 3–4 bedroom home; pump every 3–5 years as a starting point. More frequent pumping may be needed with high water use, disposal considerations, or older tanks.
• Signs you need a pump sooner: standing water, gurgling sounds, or odors near the septic tank or drainfield; unusually lush spots above the drainfield; slow drains throughout the house.

How to coordinate pumping (steps)

1. Locate the tank and confirm the tank size with past records or a licensed pump contractor.
2. Schedule a licensed septic pumper (in Brownsville, use a contractor familiar with Oregon OWTS requirements).
3. Clear access to the tank and ensure the area is safe for workers.
4. Have the pumper inspect the tank, remove solids, and note any structural issues or baffles that may need attention.

Drainfield care in Brownsville

The drainfield is the heart of the system and is especially vulnerable to Brownsville's wet winters and clay soils.

• Never drive or park on the drainfield. Heavy loads compact the soil, reducing infiltration and increasing risk of failure.
• Protect trees and shrubs. Roots can infiltrate the system and clog or damage pipes.
• Maintain a setback zone. Keep the area free of deep landscaping changes, septic-safety products, and chemical use that could harm beneficial soil biology.
• Be mindful of groundwater. In seasons with high water, reduce water use where possible to avoid saturating the drainfield.

Daily and seasonal practices that protect Brownsville systems

• Spread out laundry and dishwashing to avoid overloading the system at once. Use high-efficiency appliances and consider a laundry schedule that avoids back-to-back large loads.
• Only flush toilet paper and human waste. Avoid flushing wipes (even "flushable" types), feminine hygiene products, and nonbiodegradable items.
• Use septic-safe cleaners in moderation; avoid caustic or solvent-heavy products that can disrupt beneficial bacteria.
• Prevent FOG problems. Collect fats, oils, and greases in a container and dispose of them in the trash, not the sink or disposal. If you have a garbage disposal, limit its use and run plenty of water to help solids move through the system.
• Conserve water in winter when soils are more prone to saturation. Shorter showers, fix leaks promptly, and consider water-saving fixtures.

Seasonal monitoring and inspection

• After heavy rains or snowmelt, inspect for surface wetness, strong odors, or slow drainage inside the home.
• Schedule a professional OWTS inspection if you notice persistent drainage problems, backing up, or unusual lush growth above the drainfield.
• Have the system parameters checked during regular pumping visits (baffles, pump chambers, and intact seals).

When to call a professional

• Backups, sewage odors, or wet spots above the drainfield.
• Visible effluent surfacing or a strong drainfield odor.
• Recurrent clogs or persistent slow drainage in multiple fixtures.
• If you're uncertain about tank location, size, or access, or if you suspect root intrusion or pipe damage.

Official resources

• Oregon Department of Environmental Quality (DEQ) – Onsite Wastewater Treatment Systems (OWTS): guidance for homeowners and maintenance requirements (www.oregon.gov/deq/wq/programs/onsite-wastewater/Pages/index.aspx)
• Oregon State University Extension – Septic systems and maintenance tips tailored for homeowners (extension.oregonstate.edu/topic/home-maintenance/septic-systems)
• Linn County health and environmental resources (public health guidance for private wastewater systems in the region): co.linn.or.us/publichealth

Cost Expectations for Septic Services in Brownsville

Septic Tank Pumping and Cleaning

• What it includes: removing accumulated sludge and scum from the tank, servicing baffles and inlet/outlet pipes as accessible, and a basic onsite inspection of tank condition. In Brownsville, many homes are on older systems with smaller or single-compartment tanks, so access and tank age influence price. Disposal of pumped waste at an approved facility is included in service with licensed haulers.
• Brownsville-specific considerations: remote properties and varied access can affect travel time and crew setup, sometimes increasing the quoted price. If the tank has two tanks or a larger capacity (1,500 gallons or more), expect higher costs.
• Typical cost in Brownsville: roughly $275–$650 per tank, depending on tank size, access, and whether there are multiple tanks.
• Preparation steps:
  1. Locate the tank lid and ensure clear access.
  2. Limit water use 24 hours before pumping to ease the job.
  3. Have records ready for previous pumping or maintenance.
• Learn more: EPA septic systems overview:

Drain Field Evaluation, Repair, and Maintenance

• What it includes: diagnostic tests (visual signs, soil moisture checks, and sometimes dye tests), inspection of perforated pipes, assessment of trenches, and recommended repairs such as header/line replacement, effluent dispersal improvements, or soil amendments.
• Brownsville-specific considerations: clay-rich soils in parts of the area can lead to slower drainage and more frequent field maintenance or partial reseeding of the absorption area. Early repair can extend life without full replacement.
• Typical cost in Brownsville: $3,000–$12,000 for repairs, depending on the extent (partial trench repair vs. full field replacement). More complex fixes or moving to a mound system can push higher.
• Steps to prepare:
  1. Identify symptoms (wetness, odors, lush grass over the field).
  2. Have a licensed pro assess drainage patterns and seasonal saturation.
  3. Obtain a written repair plan and warranty details.
• Learn more: EPA septic systems overview: https://www.epa.gov/septic

Drain Field Replacement and Mound System Installation

• What it includes: complete redesign and installation of a new drain field, or construction of a mound system when soils aren't suitable for conventional absorption beds. Includes site evaluation, permitting coordination, trenching, piping, soil amendments, and final system testing.
• Brownsville-specific considerations: in clay-dominant soils or high water table areas, a mound or alternative system is more common; access to fill material and backfill stability can influence cost and schedule.
• Typical cost in Brownsville: $10,000–$40,000 (conventional replacement on the lower end; mound or specialty systems can exceed $40,000).
• Steps to prepare:
  1. Complete soil evaluation and system design with a licensed designer.
  2. Secure local permits and any necessary engineer notes.
  3. Plan for 2–5 days on-site work, with access and staging areas arranged.
• Learn more: Oregon DEQ onsite wastewater information: https://www.oregon.gov/deq/HSEW/wastewater/onsitewastewater/Pages/index.aspx

Septic Tank Riser/Lid Installation and Access Improvements

• What it includes: adding or raising concrete lids or risers for easier future maintenance, improving access and reducing the risk of buried lids during yard work.
• Brownsville-specific considerations: if the tank is older, lids may be buried or difficult to access, increasing initial labor and materials costs.
• Typical cost in Brownsville: $150–$600 for risers and lids; higher if extensive grading or concrete work is needed.
• Steps to prepare:
  1. Identify tank access points and existing risers.
  2. Align new riser height with grade and future access needs.
  3. Confirm local waivers or inspection requirements after installation.
• Learn more: EPA septic systems overview: https://www.epa.gov/septic

Emergency and After-Hours Septic Service

• What it includes: urgent pumping, repairs, or field work outside normal business hours, often with travel surcharges and after-hours labor rates.
• Brownsville-specific considerations: rural properties may require longer travel times; add-ons like ponding removal or night-time access can influence pricing.
• Typical cost in Brownsville: elevated rates, commonly 1.5–2x standard service, plus any travel charges.
• Steps to prepare:
  1. Confirm availability for after-hours service.
  2. Have a list of recent maintenance and known issues ready.
  3. Request a written estimate before work begins whenever possible.
• Learn more: EPA septic systems overview: https://www.epa.gov/septic

Permitting and official guidance:

• Oregon DEQ Onsite Wastewater Program: https://www.oregon.gov/deq/HSEW/wastewater/onsitewastewater/Pages/index.aspx
• EPA Septic Systems: https://www.epa.gov/septic