Adding a bedroom, building an ADU, or refreshing your kitchen? If your Kitsap County home runs on a septic system or a private well, a remodel touches more than design. It can affect permits, timelines, and your budget. The good news: with a clear plan, you can avoid surprises and move your project forward with confidence. In this guide, you’ll learn the key triggers, setbacks, inspections, timelines, and costs that matter in Kitsap, plus a simple checklist to get started. Let’s dive in.
Why septic and well rules matter
Kitsap Public Health District updated its local onsite sewage ordinance on March 17, 2025 to align with state rules. The update reflects statewide changes that began in 2024 and continue to roll out. You can review the local update and statewide rule overview for context and timing:
- Review the local ordinance update at Kitsap Public Health District.
- See the state’s rule revision and effective dates from the Washington Department of Health.
KPHD administers septic and private well reviews while Kitsap County Department of Community Development (DCD) issues building permits for unincorporated areas. Many additions and ADUs require Health District review before DCD can issue a building permit. Planning with these agencies in mind will save you time.
Review the local ordinance update at Kitsap Public Health District
See the state’s rule revision and effective dates
What triggers a Health District review
You typically need Health District review if your project:
- Increases floor area beyond the original exterior walls.
- Adds a bedroom or increases sleeping capacity.
- Adds plumbing fixtures or changes use in a way that increases wastewater flow.
- Builds an ADU, guest house, or connects a new structure to the existing system.
Small interior-only work that does not add bedrooms usually does not require Health District review. When in doubt, contact KPHD early to confirm what your project needs.
Septic capacity basics you should know
Septic design capacity in Washington is based on bedrooms. State rules use a minimum design flow of 120 gallons per bedroom per day for single-family homes. Minimum septic tank sizes also track bedroom count, such as 1,000 gallons for up to four bedrooms, plus 250 gallons for each additional bedroom.
If you add a bedroom, KPHD will compare your proposal with the system’s permitted capacity and the available reserve area. If capacity is short or no reserve exists, you may need an expansion or replacement. Alternative treatment systems often require an active maintenance contract and current maintenance records for approvals.
See septic design flow and tank sizing in WAC 246‑272A‑0230
Private wells: tests, capacity, and reports
For private wells, KPHD typically requires specific evidence of water adequacy for certain projects, especially bedroom adds, ADUs, or replacement homes. Expect to provide a well construction report (well log), a pump test that often demonstrates at least 5 gallons per minute per residential connection, plus recent bacteriological and chemical testing. In Kitsap, the “Kitsap 5” chemical panel commonly includes iron, manganese, nitrate, chloride, and conductivity.
At the time of sale, KPHD requires Water Status Reports for properties on one- or two-party wells or Group B systems. In 2024, about 39 percent of private water status reports identified significant issues. If you plan to remodel or sell, consider testing early to avoid delays later.
Review KPHD’s private well requirements
Learn about Water Status Reports and related processes
Setbacks, site plans, and waivers
Setbacks drive what you can build and where. Washington well standards require at least 50 feet from a well to a septic tank or pump chamber and 100 feet from a well to the edge of the drainfield and reserve area for private wells. These distances are common constraints when you try to push out a wall or place an ADU.
Your site plan needs to show buildings, septic components, the reserve area, wells, slopes, and sensitive areas at scale. Incomplete plans are a leading cause of review delays. If you cannot meet setbacks, certain waivers or variances may be possible, sometimes requiring added treatment or separate agency review. Start that conversation early if your property is tight.
Check Washington’s minimum well-to-septic setbacks
Permits, inspections, and timelines
Plan for coordination across agencies. DCD issues building permits and sets review timelines, which can vary by project and season. KPHD conducts septic inspections for new connections and component changes; do not cover work until you have an inspection and approval.
Building finals can be delayed without KPHD signoff, so schedule inspections carefully. Early coordination helps you avoid multi-month delays tied to resubmittals or missing documentation.
Schedule septic-related inspections and requests with KPHD
Check Kitsap County DCD’s permit pathways and timelines
Budget, costs, and financing options
Septic costs vary widely based on site conditions, soils, and system type. Regional cost guides put typical new installations or replacements in the low thousands to tens of thousands of dollars. Your total budget should include design fees, permits, potential site work, and contingency for unknowns.
If you need to repair or replace a system, Kitsap participates in the Craft3 Clean Water Loan program, which can finance design, permitting, and installation for many homeowners. Review program steps and eligibility before you finalize scope.
See typical septic system cost ranges
Explore the Craft3 Clean Water Loan program
A simple planning checklist
Use this checklist to keep your project moving:
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Search records first
- Pull KPHD septic records and as-builts. If records are missing, KPHD will guide discovery steps. Missing records often cause delays.
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Call KPHD before you design
- Confirm whether you need a Building Clearance or Building Site application and what documentation is required. This prevents rejected building permit applications.
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Build a complete site plan
- Include buildings, septic components, the reserve area, well locations, setbacks, slopes, and sensitive areas to scale. Hire a licensed OSS designer or engineer if required.
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Verify septic capacity early
- Compare your bedroom count to the permitted design flow and tank size. If your remodel exceeds capacity, plan for an expansion or replacement.
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Check well adequacy
- Gather the well log, schedule a pump test if needed, and complete bacteriological and chemical tests. Address water production or quality issues early.
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Confirm setbacks and possible waivers
- Measure well-to-tank and well-to-drainfield distances. If you cannot meet minimums, discuss waiver options and any added treatment early.
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Plan for inspections and records
- Do not cover septic connections before inspection. Submit Records of Construction for component changes to maintain a clean file for finals and future sales.
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Align your permit timeline
- DCD review cycles and Health District timelines vary. Early engagement reduces the risk of multi-month delays.
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Budget for the unexpected
- Include design, permits, excavation, treatment components, and contingency. If needed, evaluate Craft3 financing for repairs or replacements.
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Track rule changes if you plan to sell
- State rules introduce staged property-transfer inspection requirements, with more documentation expected at sale in coming years. Staying ahead helps you avoid last-minute surprises.
See the state’s rule revision and effective dates
Ready to map your remodel or prep a property for sale? Local knowledge and a tight plan make all the difference. If you want a second set of eyes on scope, timing, and resale implications in Kitsap County, reach out to Christopher Threet | Greater Peninsula Properties for a straightforward, local strategy.
FAQs
Adding a bedroom on septic in Kitsap County
- Not always. KPHD checks your permitted design flow by bedroom count and the reserve area. If capacity is short, you may need a system expansion or replacement.
Building an ADU on a property with a well
- Expect to show water adequacy with a well log, pump test, and water quality tests. Setback conflicts with the drainfield or reserve area often drive ADU placement.
Common septic setbacks to watch
- For private wells, Washington standards require at least 50 feet to a septic tank and 100 feet to the drainfield or reserve. Measure early in design.
How inspections affect your timeline
- KPHD inspections are required before covering septic work, and DCD finals depend on KPHD signoff. Schedule ahead to avoid last-minute delays.
Typical costs and financing for repairs
- Costs vary from the low thousands to tens of thousands depending on soils and system type. Many homeowners use the Craft3 Clean Water Loan program to finance design and installation.
