Franklin County, Washington requires county-issued building permits and inspections for dwellings and most buildings before use or occupancy1. Franklin County Planning and Economic Development handles construction permitting and zoning in unincorporated areas, while Benton-Franklin Health District permits and inspects qualifying septic systems2,3,4.
Do you need a building permit in Franklin County, Washington?
Yes.
Yes. Franklin County requires county-issued building permits and inspections for dwellings and most buildings before use or occupancy1. Permit submittals must follow the 2021 IRC, IBC and Energy Credit Code standards11. Franklin County publishes separate forms for residential work, additions, remodels, demolition, grading and several land-use reviews11. Building, plumbing and mechanical fees are paid when the permit is issued and can be estimated beforehand7. An owner working on their own property may qualify for Washington's contractor-registration exemption, but that exemption does not remove the building-permit requirement and does not apply when the work is for sale, demolition or lease6.
Who is the Franklin County building department, and how do you reach them?
The Franklin County Planning and Economic Development Department administers construction permitting and inspection, land-use permitting, long-range planning and code enforcement.
The Franklin County Planning and Economic Development Department administers construction permitting and inspection, land-use permitting, long-range planning and code enforcement2. Its office is at 502 W Boeing Street in Pasco; call 509-545-3521 or email planninginquiry@franklincountywa.gov with building or zoning questions2. Ask which published building or planning application fits the work, whether grading or floodplain review is separate, and what inspections must be completed before occupancy1,11. Franklin County requires the appropriate floodplain-development approval before work begins in a floodplain1.
Does Franklin County have zoning?
Yes.
Yes. Franklin County applies its Zoning Ordinance in unincorporated areas; incorporated municipalities may administer their own land-use rules3. Confirm the parcel's district with Planning and Economic Development because setbacks, frontage, shoreline buffers and critical-area buffers can affect placement1,2. The available material does not provide a complete current list of districts or all dimensional standards12. Limited agricultural uses on parcels larger than 2.5 acres may qualify as permitted uses only in specified districts after site inspection and verification by the planning director; that is not a blanket exemption from building or land-use requirements13.
How do septic permits work in Franklin County?
Benton-Franklin Health District permits, oversees design and installation, and inspects on-site septic systems with wastewater flows below 3,500 gallons per day.
Benton-Franklin Health District permits, oversees design and installation, and inspects on-site septic systems with wastewater flows below 3,500 gallons per day4. Contact the district's Pasco office before fixing the house location or site plan4. About 41% of Franklin County soils rate free of severe limits for a conventional drain field, so do not assume a standard system will fit every parcel14. We could not confirm which alternative off-grid sanitation methods Franklin County accepts; ask Benton-Franklin Health District before planning anything other than an approved septic or sewer connection4.
Can you live in an RV or tiny home on your land in Franklin County?
Franklin County allows temporary occupancy of a mobile home, travel trailer, RV or fifth wheel for family hardship, while building a residence, or for farm family or farm labor, but a temporary permit from the planning department and health- and building-department approvals are required.
Franklin County allows temporary occupancy of a mobile home, travel trailer, RV or fifth wheel for family hardship, while building a residence, or for farm family or farm labor, but a temporary permit from the planning department and health- and building-department approvals are required8. These permits generally run for six months and may be extended for one additional six-month period after conditional-use approval8. An RV park requires a special or conditional use permit, is limited to specified zoning districts, and needs at least four acres9. These rules do not establish general long-term RV living on any private parcel. We could not confirm a Franklin County rule for tiny-home occupancy; ask Planning and Economic Development whether the parcel's zoning allows the proposed home and what building, septic and land-use approvals apply2.
Building a home in Franklin County: the steps, in order
Call Franklin County Planning and Economic Development at 509-545-3521 to confirm the zoning district, setbacks, frontage and required applications.
- Call Franklin County Planning and Economic Development at 509-545-3521 to confirm the zoning district, setbacks, frontage and required applications1,2.
- If the home will use septic, contact Benton-Franklin Health District at 509-547-9737 before fixing the site plan4.
- Prepare the building submittal to the 2021 IRC, IBC and Energy Credit Code standards11.
- Obtain any separate grading or floodplain approval and, in unincorporated Franklin County, a road-approach permit for construction valued at $25,000 or more1,10.
- Request a fee estimate; building, plumbing and mechanical fees are due when the permit is issued7.
- Complete the required building and septic inspections before use or occupancy1,4.
What to check before you buy land in Franklin County
Confirm the parcel's zoning district, setbacks and legal buildability with Franklin County Planning and Economic Development.
Confirm the parcel's zoning district, setbacks and legal buildability with Franklin County Planning and Economic Development1,2,5. Short plats and long plats are regulated in unincorporated Franklin County, so do not assume a large tract can be divided as proposed11,15. Ask Benton-Franklin Health District about septic feasibility; roughly 41% of county soils rate free of severe limits for a conventional drain field14. Check floodplain status and road access before choosing a house site1,10. We could not confirm a universal water or sewer connection rule or the exact private-well approval path, so ask the building and septic offices what applies to the parcel2,4. The median property-tax bill is about $2,638 per year, with an effective rate near 0.8%14.
Watch-outs
Sources
15 official pages, each quoted and re-checked · written October 10, 2026
- franklincountywa.gov
- Franklin County Planning and Economic Development Department (franklincountywa.gov)
- Code Enforcement Program
- On-Site Sewage
- Franklin County GIS
- RCW 18.27.090 — Exemptions
- Building Fees
- Franklin County Code § 17.66.250 — Temporary use of a trailer
- Franklin County Code § 17.64.030 — Conditional use permit required
- New Residential Dwelling Application Packet
- Application Forms
- Plans & Ordinances
- Franklin County Code Title 17 text amendment document
- Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
- Current Planning
Written October 10, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.
Off-grid gear
Going off-grid in Franklin County means bringing your own water and power. The kit we’d start with:
- Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
- Power Bluetti Solar generators and home battery backup for living off the grid.
- Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
- Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.
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