Septic in Kenwood, CA

Last updated: Mar 21, 2026

Nestled among the vineyards and pine-studded hills of Kenwood, you'll notice a common thread in many homes: wastewater that's managed right on the property. Here in this part of Sonoma County, septic systems are a familiar, practical choice that fits the landscape and lifestyle we love.

Is septic common in Kenwood? Should I expect septic if I own or buy a home? Yes. Kenwood has a mix of rural lots, hillside properties, and areas where public sewer lines haven't extended. That means a septic system is a common and sensible setup for many homes here. If you're buying, plan to encounter a septic system or at least a clear record of one. It's smart to have a thorough septic inspection as part of your due diligence—tank size, condition, drain field performance, and any needed repairs can influence your long-term costs and comfort.

Why homes typically use septic systems in Kenwood

  • Rural character and lot geometry: Many properties are spread out on hillsides or in vineyard-adjacent spaces where tying into a central sewer is impractical or prohibitively expensive.
  • Limited sewer infrastructure: Public sewer lines haven't reached every nook and cranny of Kenwood, so on-site treatment remains the practical norm.
  • Environmental stewardship: On-site systems allow wastewater to be treated close to home while protecting soil, groundwater, and nearby creek corridors when they're properly designed and maintained.
  • Cost and feasibility: Extending sewer lines across rugged terrain isn't just expensive—it can also be disruptive to mature landscapes. Septic systems offer a more immediate solution for home comfort and property values.

High-level explanation (why septic exists here)

The combination of rolling terrain, soil conditions, and the historical pace of development means centralized wastewater infrastructure often isn't feasible. Septic systems provide a reliable, on-site way to manage wastewater without relying on a distant sewer grid. When designed, installed, and maintained correctly, they work quietly in the background—keeping your home comfortable and your environment protected.

As your neighbor and a local septic contractor, I'm here to help you navigate the basics with practical, down-to-earth guidance. If you're evaluating a property, consider: basic system type, tank size, permit history, recent pumping, and the condition of the drain field. Small steps now can save big headaches later. In Kenwood, practical know-how and a steady, straightforward approach keep septic decisions feeling like good common sense rather than a mystery.

Where Septic Systems Are Common in Kenwood

Map of septic coverage in Kenwood, CA

Why septic is common in Kenwood

Kenwood sits in a largely rural, hillside part of Sonoma County where municipal sewer service is limited or unavailable. Many homes on larger parcels rely on on-site wastewater treatment systems (OWTS) to manage household waste. Older homes built before sewer lines reached the area often stayed on septic, and newer homes on rural lots continue to use private systems because installing a sewer main is costly or impractical in the terrain. This pattern is typical of Kenwood's winding roads, vineyards, and hillside estates.

Where in Kenwood you will typically find septic systems

  • Outside the sewer service boundaries: Homes on unincorporated lands or parcels not connected to a municipal sewer district.
  • Rural and hillside parcels: Properties with sloped terrain or terraced lots where gravity sewer is difficult to install.
  • Vineyards and larger estate properties: Larger lots often use private OWTS to accommodate extended residential or commercial-use buildings.
  • Older buildings and homesteads: Homes built before sewer expansion in the region commonly rely on septic systems and may have historic design details to maintain.

Terrain and soils that shape septic design in Kenwood

  • Sloped terrain: Leach fields on slopes require careful layout to prevent erosion, surface runoff, or drainage issues.
  • Soil variety: Kenwood soils range from well-drained loams to heavier clays; percolation rates and soil depth influence system sizing and placement.
  • Shallow bedrock and groundwater: In certain spots, shallow soils or perched water can affect tank placement, absorption field depth, and seasonal performance.
  • Tree roots and vegetation: Olive, redwood, or other tree roots near absorption fields can interfere with function; plant carefully around any leach field.

How to locate and verify your septic system

  1. Check your property records and permit history with the county to find OWTS design, pump, and inspection notes.
  2. Look for visible components and access ports; a licensed septic contractor can locate tanks and leach fields using expertise and, if needed, electronic locating tools.
  3. If you're unsure, contact your local environmental health department for records and guidance on system type, year installed, and maintenance requirements.

Maintenance basics for Kenwood homes

  • Pumping schedule: Most households pump every 3-5 years, but frequency depends on tank size, number of occupants, and water use. A local septic contractor can tailor a schedule for your home.
  • Regular inspections: Have a licensed professional inspect the system during pumping to check baffles, filters, and the condition of the leach field.
  • Water-use practices: Use water-saving fixtures, spread out high-water-use tasks, and avoid flushing non-biodegradable items to reduce load on the system.
  • Landscape considerations: Keep heavy equipment and vehicles off absorption fields; plant shallow-rooted groundcovers rather than deep-rooted trees directly over the field.

Official resources

  • Sonoma County Environmental Health – Septic Systems:
  • California Department of Public Health – Onsite Wastewater Treatment Systems (OWTS):
  • EPA – Septic Systems: https://www.epa.gov/septic

Septic vs Sewer: What Homeowners in Kenwood Should Know

Determine if you have septic or sewer

  1. Check your utility bill. If you're billed by a sewer utility, you're on public sewer; if there's no sewer charge, you likely have a septic system.
  2. Look in your yard for a septic tank lid, distribution box, or access port, or for a curb stop/cleanout near the property line. A visible on-site tank usually means septic.
  3. Contact your county wastewater utility or local permit office to confirm whether your property connects to a municipal sewer and if a sewer lateral exists.

Septic vs Sewer: the big picture

  • Septic system: private, on-site treatment; you're responsible for maintenance and repairs; performance depends on proper use and regular pumping.
  • Public sewer: wastewater is taken away by the municipal system; the utility handles maintenance; homeowners pay ongoing service charges.

Maintenance responsibilities and best practices

  • If you have a septic system:
    • Pump every 3–5 years (interval depends on tank size, household size, and usage); have periodic inspections by a licensed professional.
    • Protect the drainfield: keep heavy equipment and trees off it; direct roof and surface water away; ensure proper grading and drainage around the area.
    • Conserve water and use a septic-safe approach: fix leaks, install efficient fixtures, spread laundry across the week.
    • Avoid flushing or disposing of oils, solvents, paints, pesticides, wipes labeled flushable, sanitary products, or food waste through the garbage disposal.
  • If you have public sewer:
    • Do not flush non-biodegradable items, fats, oils, and greases; use screens on drains to catch hair and debris.
    • Be mindful of excessive water use to reduce the load on the system and minimize backups during heavy rainfall or outages.
    • If you notice slow drains, sewer odors, or backups, contact the utility promptly.

Costs and timing to plan for in Kenwood

  • Septic system:
    • Pumping and inspections: recurring costs every few years; costs vary by tank size, access, and local rates.
    • Repairs or drainfield replacement: potential high-cost, so budgeting for long-term maintenance is wise.
  • Public sewer:
    • Connection fees if not yet connected; ongoing monthly or quarterly service charges based on locality and usage.
    • Sometimes, system upgrades or capacity changes can affect rates; check with your sewer provider for the latest schedules.

How to decide for your Kenwood property

  1. Compare current maintenance costs (pumping, repairs) against sewer charges and any monthly service fees.
  2. Consider resale implications: some buyers prefer or require a connected sewer; others value on-site independence.
  3. If unsure about system condition or feasibility of switching, consult licensed septic professionals and your local wastewater utility for a formal assessment and options.

Official guidance and resources

  • California State Water Resources Control Board – Onsite Wastewater Treatment Systems (OWTS) program:
  • U.S. EPA – Septic systems: https://www.epa.gov/septic

Typical Septic System Types in Kenwood

Conventional gravity septic systems

Most homes in Kenwood rely on gravity-flow systems: wastewater from the house flows into a septic tank, solids settle, liquids exit to a buried drainfield, and effluent seeps into the soil. These work best in soils with adequate depth and permeability.

  • How it works: a pair of chambers or a single tank traps solids; clarified effluent moves into a drainfield via gravity.
  • Site notes: need enough horizontal soil width for the drainfield and adequate soil percolation; shallow bedrock or dense clay can limit performance.
  • Pros: simple, typically lower upfront cost; easy to monitor.
  • Cons: performance depends on soil conditions; improper loading or heavy use can shorten life.

Pressure distribution and mound systems

When soils are shallow, very wet, or poorly permeable, Kenwood homes may use pressure-dosed or mound designs. Pressure distribution delivers evenly dosed effluent across the drainfield, reducing the risk of clogging, while mound systems place the drainfield in an elevated, engineered soil raised above the natural grade.

  • Pressure distribution: uses a pump or blower to evenly distribute effluent to multiple trenches.
  • Mound systems: a sand- or gravel-filled bed built above the ground, with a shallow septic tank and a dosing system.
  • Pros: better performance in challenging soils; can increase drainfield area without increasing land disturbance.
  • Cons: higher installation cost; more maintenance requirements and power needs for dosing.
  • Local note: permitting and proper design are essential; check with the county for approved designs and setbacks.

Aerobic Treatment Units (ATU) with spray or drip dispersal

ATUs treat wastewater more aggressively than conventional systems and often use spray or drip dispersal to distribute pre-treated effluent over the drainfield.

  • How it works: an aerobic tank adds oxygen to promote microbial breakdown; treated effluent is dispersed over a dispersal area.
  • Pros: higher level of treatment; can work on smaller or marginal soils.
  • Cons: electricity and media replacement costs; regular maintenance and service contracts required.
  • Site notes: often chosen where space is limited or soil is not ideal for standard leach fields.

Chamber and bed drainfields

Modern drainfields may use open-bottomed chamber systems or shallow-reinforced beds instead of traditional gravel trenches. Chambers create wider, continuous flow spaces for effluent to infiltrate.

  • Chambers: lightweight HDPE or similar modules that create large infiltration areas.
  • Beds: shallow, engineered soil mixes under a cover; can improve performance on marginal soils.
  • Pros: easier installation, adaptable to uneven lots.
  • Cons: still soil-dependent; mis-sizing or poor loading can shorten life.
  • Local tip: ensure the system type is permitted in your area and installed by a licensed pro.

Sand filtration and ET (evapotranspiration) beds

In some Kenwood yards with limited drainage, sand filters or ET beds may be used as secondary treatments or final disposal steps.

  • Sand filter: wastewater passes through a sand layer for additional polishing before draining.
  • ET bed: uses plant transpiration and evapotranspiration to help move water away from the root zone.
  • Pros: additional treatment, reduces seepage to groundwater in sensitive soils.
  • Cons: requires careful design and maintenance; not suitable everywhere.
  • Resource note: these designs have specific soil and climate requirements.

Key steps to evaluate which type fits your site

  1. Get a soil test and percolation analysis to understand drainage and permeability.
  2. Check slope and depth to bedrock; steep or shallow sites often need alternative designs.
  3. Review water usage patterns and future needs (household size, laundry, irrigation).
  4. Consult the local permit office for approved systems and setback rules before planning.

Official resources and guidance

Common Septic Issues in Kenwood

Clay soils and slow drainage

Kenwood soils often mix clay loam with limited natural drainage, especially on hillside properties. When the drainfield can't absorb effluent quickly enough, you may notice pooling, odors, or slow flushing.

  • Symptoms
    • Water pooling or soggy areas over the drainfield.
    • Gurgling sounds in plumbing and slow drains in multiple fixtures.
    • Occasional sewer odors near the system.
  • Why Kenwood is prone
    • High clay content reduces infiltration rates.
    • Areas with shallow soils or compacted soil from vehicles or foot traffic over the field.
    • Slope and landscape features can influence drainage patterns.
  • What to do
    1. Have a licensed septic professional confirm soil percolation rates and inspect the tank and leach field (camera inspection if needed).
    2. Cut water use: fix leaks promptly, install high-efficiency fixtures, and stagger laundry to distribute wastewater more evenly.
    3. Avoid driving or planting deep-rooted trees over the drainfield; keep root zones clear.
    4. If the field is marginal, discuss options with a pro (e.g., trench improvements, dosing systems, or a mound system where permitted).
  • Official resources

Groundwater and winter flooding

Winter rains in the Sonoma Valley can raise the water table and saturate soils, increasing the risk of effluent surfacing and system backups.

  • Symptoms
    • Standing water over the drainfield after rains.
    • Foul odors or wet soils in the leach field area during wet seasons.
    • Toilets or sinks taking longer to drain after rainfall.
  • Why Kenwood is affected
    • Seasonal high groundwater in low-lying parcels.
    • Sloped lots can channel surface water toward the drainfield if grading isn't ideal.
    • Clay-rich soils hold water longer, delaying drying between storms.
  • What to do
    1. Limit irrigation and exterior water use during wet months to reduce load on the system.
    2. Keep drainage away from the drainfield path and ensure proper grading to direct runoff away from the leach field.
    3. Schedule a field assessment with a septic professional if surfacing or odors persist after rains.
    4. Consider a professional evaluation for field upgrades or alternatives if flooding occurs regularly.
  • Official resources

Tree roots and landscaping encroachment

Oak and other large roots are common around Kenwood homes and can invade drainlines, damaging pipes and reducing infiltration.

  • Symptoms
    • Slow drains, frequent backups, or unusual wet spots in the yard away from the house.
    • Visible cracks or damage in buried lines.
    • Increased maintenance needs without a clear cause.
  • Why Kenwood soils and plants contribute
    • Proximity of trees to the drainfield is common on hillside parcels.
    • Root systems seek moisture, entering drains through joints and cracked pipes.
  • What to do
    1. Have the sewer lines inspected with a camera if you notice repeated backups or damp areas.
    2. Create a root barrier or reconfigure plantings to keep root zones away from the drainfield.
    3. If roots have damaged lines, replace the affected section and consider upsizing or upgrading to more robust piping.
    4. Maintain a safe setback distance between landscaping and the drainfield per local codes.
  • Official resources

Slope, drainage, and site constraints

Sloped Kenwood lots can complicate drainage, siting of the drainfield, and maintenance access.

  • Symptoms
    • Uneven drainage, ponding in lower areas, or erosion around the system.
    • Difficulty accessing the tank for pumping or inspection.
  • Why it matters
    • Steep grades can limit suitable space for drainfields and increase risk of surface runoff affecting the system.
    • Poor grading can direct water across the field rather than away from it.
  • What to do
    1. Have a professional assess suitable locations for drainfield placement given slope.
    2. Implement grading strategies to direct surface water away from the system.
    3. Consider alternative or enhanced systems if standard drainfields are not feasible due to site constraints.
    4. Schedule regular inspections and pump-outs to catch issues early.
  • Official resources

System age, maintenance gaps, and improper use

Older systems are more susceptible to failure, and maintenance gaps are common in areas with limited access or awareness.

  • Symptoms
    • Frequent backups, slow drainage, odors, or lush areas above a drainfield indicating effluent.
    • Tank baffles degraded or sediment buildup visible during inspection.
  • Why it happens in Kenwood
    • Many homes have older installations that weren't upgraded or regularly pumped.
    • High irrigation or outdoor water use can accelerate solids buildup in tanks.
  • What to do
    1. Pump and inspect every 3–5 years (or per the installer's guidance) and replace any failing baffles.
    2. Track water use and fix leaks; avoid using garbage disposals routinely if wastewater volume is high.
    3. Schedule professional inspections after heavy rainfall or before property transactions.
    4. Plan for system upgrades if the current setup approaches or exceeds its useful life.
  • Official resources

Water use and fixture efficiency

While Kenwood's climate favors conservation, excessively high wastewater flow can overwhelm small or aging systems.

  • Symptoms
    • Short intervals between pump cycles, backups during peak usage, or frequent clogs.
  • What to do
    1. Install high-efficiency fixtures (low-flow toilets, aerated faucets, efficient showerheads).
    2. Space out loads that use significant water (laundry, dishwashing) to distribute wastewater more evenly.
    3. Use a compliant, properly sized disposal method and limit garbage disposals.
  • Official resources

Septic Inspection, Permits & Local Oversight

Local Oversight in Kenwood, CA

Kenwood sits in unincorporated Sonoma County, so the county's Environmental Health Division is your primary point of contact for septic systems. They handle OWTS (onsite wastewater treatment systems) permits, plan reviews, inspections, and compliance notices. In practice, homeowners work with county staff to obtain permits for new systems, repairs, or upgrades, and to schedule the required inspections at key milestones.

  • Primary contact: Sonoma County Environmental Health (SCEH) is the typical path for septic-related permits and inspections.
  • What to expect: formal plan review, permit issuance, on-site inspections, and a final approval before the system operates.

Official resources:

  • Sonoma County Environmental Health:
  • Septic Systems (county page with guidance and forms):
  • California Water Resources Control Board septic information:

The Inspection Process

Inspections occur at key stages to verify design adherence, material quality, and proper installation.

  • Step-by-step timeline:
    1. Pre-approval or plan review: county staff check that your designs meet minimum setbacks and soil requirements.
    2. Footing/ trench and tank installation inspection: inspectors confirm layout, tank placement, baffle orientation, and access risers.
    3. Drain field/seepage area inspection: soil absorption area placement, pipe grades, and backfill conditions.
    4. Final inspection: system operates as designed; all components installed per plan; paperwork and as-built drawings are in order.
  • What inspectors typically verify:
    • Setbacks from wells, streams, property lines, and buildings
    • Tank type, baffles, pump chambers, and lids for accessibility
    • Proper pipe slopes, cleanouts, and distribution networks
    • Soil absorption bed or mound installation and compaction
    • Proper venting, lids, and site restoration after work

During Construction: What to Prepare

  • Have your plans, permits, and any required reports readily accessible for inspectors.
  • Coordinate with licensed professionals to ensure workmanship aligns with approved plans.
  • Schedule inspections promptly when milestones are reached to avoid delays.

After Completion and Maintenance

  • Retain all permit documents, as-built drawings, and final inspection approvals.
  • Establish a routine maintenance schedule (pumping, inspections) per county guidance and the system design.
  • Recordkeeping helps future property transactions and any future repairs or upgrades.
  • Maintenance basics:
    • Routine pumping based on usage and tank size (commonly every 3–5 years, but your design may vary)
    • Regular checks for surface pooling, odors, or drainage issues
    • Keep a spare copy of the system diagram and maintenance records on file

Official resources:

Septic Maintenance for Homes in Kenwood

Kenwood-specific challenges

  • Hilly terrain and clay-rich soils common to many Kenwood properties slow absorption, which can increase the risk of surface pooling after rainfall.
  • Winter rainfall in Sonoma County can saturate soils and push effluent toward the surface or the groundwater table, stressing the drain field.
  • Proximity to mature oak trees and other vegetation means root systems can intrude on underground lines and disrupt the leach field.
  • Slope and drainage patterns matter: improper grading around the system can direct surface water toward the septic area, reducing treatment efficiency.
  • Variable property sizes and older installations mean some systems were designed for smaller households or different usage patterns; households with more occupants or frequent water use may need more attentive maintenance.

Routine maintenance you can do today

  • Maintain a simple servicing log: date of inspections, pumping, and any repairs. Note how many bedrooms, typical daily wastewater flow, and any changes in usage.
  • Use water efficiently: install ultra-low-flow toilets, fix leaks promptly, run dishwashers and washing machines only with full loads, and spread high-volume uses (like laundry) over the day.
  • Use septic-safe products: avoid harsh chemical cleaners, solvents, or septic tank additives unless advised by your pro. If in doubt, ask a licensed contractor or refer to EPA guidance at can help you understand state-wide standards.

Pumping and inspection schedule (Kenwood-focused)

  1. Annual visual check (do-it-yourself between visits): look for damp patches, odors, or surface effluent near the drain field; verify there are no new trees or heavy roots encroaching.
  2. Professional inspection every 1–3 years: a licensed septic contractor confirms tank integrity, filters, and overall system performance; adjust pumping interval as needed.
  3. Pump-out window: most Kenwood homes with typical usage need pumping every 3–5 years; more frequent pumping may be required in high-flow situations or after an inspection indicates sludge buildup.

Protecting your leach field in Kenwood

  • Keep the drain field clear of heavy equipment, parking, and new construction activity.
  • Maintain 25–50 feet of clearance around large trees to minimize root intrusion (adjust based on local guidance from your inspector).
  • Improve surface drainage away from the system with properly sloped turf or approved drainage features.
  • If you're planning landscaping, choose shallow-rooted plants and avoid deep excavation near the field.

Signs of trouble and when to act

  • Slow drains, gurgling noises, or sewage odors inside the home.
  • Damp, soggy patches or lush, unusually green spots above or near the drain field.
  • Backups in toilets or commercial devices that repeatedly fail to drain.
  • If you notice any of these, contact a licensed septic professional promptly. Early intervention can prevent costly damage, especially in Kenwood's clay soils and seasonal wet periods.

Local resources and references

  • EPA Septic Systems:

Cost Expectations for Septic Services in Kenwood

Septic System Inspection and Maintenance Plans

What this includes:

  • Routine inspections of tank integrity, baffles, effluent screens, and overall system performance.
  • Heightened emphasis on evaluating the drain field's absorption area and signs of failure.
  • Recommendations for pumping intervals and any needed repairs or upgrades.

Kenwood considerations:

  • Hilly terrain and sometimes narrow / gravel driveways can affect access for inspectors and disposal trucks.
  • Clay soils and seasonal moisture can influence drain-field performance; expect possible additional evaluations.

Typical Kenwood cost:

  • Basic inspection: $150–$350
  • Maintenance visit with routine pumping: $400–$900
  • Annual maintenance plans (scheduled visits over a year): $500–$1,000

Septic Tank Pumping

What this includes:

  • Pumping out the septic tank, removing sludge, and transporting waste to an approved facility.
  • Inspection of tank condition, lids, and nearby components; minor adjustments or cleaning as needed.

Kenwood considerations:

  • Access challenges (driveways, gates) can affect pump timing and equipment needs.
  • Tank size varies; larger residential tanks (1,000–1,500 gallons) cost more to pump than smaller tanks.

Typical Kenwood cost:

  • Pumping only: $350–$900
  • Additional disposal fees or disposal-site surcharges: $50–$300
  • Tank size impact: larger tanks push toward the higher end of the range

Drain Field Evaluation and Repair

What this includes:

  • Drain-field assessment through dye tests, soil evaluation, and sometimes camera/pressure tests.
  • Repair planning if signs of insufficiency or failures appear (fixes may involve soil replacement, trench repairs, or redesign).

Kenwood considerations:

  • Sloped lots and rocky or clay soils common in the area can complicate repair work and may necessitate higher-cost solutions (e.g., mound systems, regrading).
  • Access to the drain field can influence service duration and price.

Typical Kenwood cost:

  • Evaluation and testing: $200–$600
  • Minor drain-field repair: $1,000–$3,000
  • Major repair or replacement (including possible mound/system redesign): $8,000–$25,000+ depending on scope

Septic Tank Repairs and Component Replacement

What this includes:

  • Repair or replacement of baffles, inlet/outlet components, risers, lids, pumps, or filters.
  • Addressing root intrusion, leaks, or pump failures with appropriate parts and seals.

Kenwood considerations:

  • Age of tanks (concrete vs. plastic) can affect repair options and permit requirements.
  • Access and weather can impact scheduling; some repairs require permits and inspections.

Typical Kenwood cost:

  • Minor repairs (baffles, seals, lid adjustments): $300–$1,500
  • Major component replacement (pump, filter, or valve): $2,000–$6,000
  • Complete tank replacement (rare, but possible): $6,000–$12,000+

System Replacement or Upgrade

What this includes:

  • When a system cannot be repaired economically, a full or partial system replacement (tank, drain field, or upgrade to a mound) may be needed.

Kenwood considerations:

  • Sloped or compact lots may require alternative layouts and engineered designs.
  • Local permit requirements and soil tests may add to the timeline and cost.

Typical Kenwood cost:

  • Partial replacement or field retrofit: $10,000–$25,000
  • Full drain-field replacement: $15,000–$40,000
  • Mound system or advanced treatment upgrade: $20,000–$60,000+

New Septic System Installation (for new homes or major rebuilds)

What this includes:

  • Site assessment, soil testing, engineering design, tank placement, drain-field layout, and system installation.

Kenwood considerations:

  • Terrain, setbacks, and soil conditions drive design complexity and cost.
  • Permitting, engineering approvals, and inspections add to both timeline and expense.

Typical Kenwood cost:

  • Standard system: $15,000–$40,000
  • Enhanced systems (mounds, aerobic treatment units): $25,000–$60,000+

Permitting, Planning, and Inspections

What this includes:

  • Application for permits, plan review, site evaluations, and scheduled inspections.
  • Mandatory final inspections to certify system compliance with local health and environmental codes.

Kenwood considerations:

  • Sonoma County requires proper permitting for most repairs, replacements, and new installations.
  • Permit and inspection fees vary by system type and scope.

Typical Kenwood cost:

  • Permit fees: $1,000–$3,000 (varies by project)
  • Inspection fees: $100–$300 per visit

Official resources:

  • Sonoma County PRMD – Environmental Health – Septic Systems:
  • California State Water Resources Control Board – Onsite Wastewater Programs: