Building permits, zoning and septic rules in Pierce County, Washington

Construction or renovation of a residence in unincorporated Pierce County requires a county building permit unless the work is specifically exempt¹. Pierce County administers its adopted building and fire codes through Title 17C in the county's jurisdiction². Washington lets an owner work on the owner's own property without contractor registration when the project is not being done to sell, demolish or lease the property, but building, electrical, plumbing, septic and other permit rules still apply⁷. Temporary growing structures used only to produce horticultural plants have a narrow state building-code exemption; that is not a general exemption for houses, barns or other agricultural buildings¹⁰. Puyallup, Bonney Lake, Edgewood, Milton and Fircrest issue their own building permits^{11,12,13,14,15}. Septic systems remain under Tacoma-Pierce County Health Department regulation³.

The Pierce County Development Center is the central office for building permits, land-use actions, site-development permits, environmental reviews, sewer utility permits and fire-prevention permits¹⁶. The Development Center is at the Pierce County Annex, East Entrance, 2401 S 35th St., Tacoma, WA 98409, and its phone number is (253) 798-3739¹⁶. Start with parcel research, gather the listed submittal items, prepare a site plan, upload the application materials as PDFs and track the review; Level 1 screening is required for certain projects, including properties with septic systems or private wells¹⁶. Pierce County publishes separate fee resources for construction, land use, impact and fire-prevention permits, so use the current schedule for the actual charge¹⁶. Pierce County’s published temporary certificate-of-occupancy process concerns commercial occupancy and does not replace a final certificate; ask the Development Center which inspections and final approval a residence needs^16,17.

Pierce County Planning & Public Works administers zoning in unincorporated Pierce County; incorporated parcels follow city zoning^2,18. Use the parcel number or site address to find the applicable community-plan use and dimension tables; setbacks are measured from property lines, and setback and height limits depend on the zone⁵. Rural and resource-zone lot sizes are district-specific, and land divisions and boundary changes fall under county development regulations^2,19. Lakewood, University Place, Sumner, Fife, DuPont, Milton, Fircrest, Buckley and Ruston administer their own zoning^{15,20,21,22,23,24,25,26,27}. Septic and individual-well regulation remains with the Tacoma-Pierce County Health Department³.

The Tacoma-Pierce County Health Department regulates and permits on-site septic systems and individual wells in Pierce County²⁸. The department's process includes an installation permit and final inspection, although requirements vary by system type and site conditions⁶. For a permitted repair or replacement, the installer must leave the system uncovered until the designer or engineer and Health Department inspect and approve it; the department visits within 3 business days after processing the final-inspection request, and the system cannot be used until its record drawing is approved²⁹. Only 0.8% of Pierce County soils are rated without severe limitations for a conventional drain field, so make septic feasibility an early purchase contingency³⁰. Call (253) 649-1500 or visit 3629 S. D St., Tacoma, WA 98418-6813³¹.

Pierce County does not allow an RV, travel trailer or tent to serve as an indefinite dwelling in unincorporated areas; ordinary occupancy requires a temporary-use permit, and more than 120 days in any 12-month period counts as permanent occupancy outside the stated exceptions⁴. An undeveloped lot inside the unincorporated Urban Growth Area is stricter: an RV, travel trailer or tent cannot be occupied unless the lot qualifies for the shoreline exception³². A park-model tiny home is treated as an RV and needs no building permit for the vehicle itself, although other approvals may apply: recreational placement requires a Temporary Use Permit and is limited to 120 days per year, while permanent placement is allowed in a mobile home park or as a Temporary Housing Unit for Family⁸. A site-built tiny home is under 400 square feet, excluding its sleeping loft, and must meet residential and energy codes, setbacks, driveway and lot-coverage rules, and approved water and sewage requirements; composting or incinerator toilets and rainwater catchment for potable water are not allowed⁸. Factory-built tiny homes follow manufactured-home permitting and state factory-built standards⁸.

1. Confirm that the parcel is unincorporated, then look up its zone and the applicable use, setback, lot-coverage and height tables before choosing a plan^5,8,18.
2. Research the parcel, assemble the required submittal items, prepare the site plan and complete Level 1 screening when the property's conditions require it¹⁶.
3. For land without sewer, obtain the applicable septic approval and installation permit from the Tacoma-Pierce County Health Department^6,28.
4. Obtain Planning & Public Works approval for work in a county right-of-way, or written WSDOT permission for a state-highway connection^33,34.
5. Show the 100-year flood-hazard area on plans for a potentially affected site and complete any required studies or floodplain review^35,36.
6. Submit the residential building-permit package, pay the charges in the current county fee schedule and schedule the required inspections^1,16,37.

Confirm whether the parcel is in a city or unincorporated Pierce County, then verify its zone, minimum lot size, setbacks, lot coverage and height limit^5,8,18,19. If you plan to divide land or adjust a boundary, account for Pierce County's land-division rules before relying on a proposed parcel layout². Do not plan on an RV as indefinite housing, and do not assume an undeveloped urban lot can host one even temporarily^4,32. Verify flood hazards and driveway authority before treating a building site as usable^33,35. Pierce County's effective property-tax rate is about 0.9%, and its median annual property-tax bill is about $4,555³⁰. Short-term vacation rentals in single-family homes or ADUs require an affidavit to Planning & Public Works stating intent, contact information and advertising sites³⁸.