Dry Columbia Basin sagebrush steppe with basalt cliffs above a wide river and green irrigated vineyard rows at its edge.
Franklin County, Washington Tri-Cities & Walla Walla

Barndominium Builders in Franklin County, Washington

Franklin County is mostly farm country, and the County says so plainly in its Code of the West: much of the rural land is actively used for crops, livestock and mineral resources, and water, sewer and power may not reach urban standards. For a barndominium buyer that is the appeal and the checklist in one. Outside Pasco and the county's small towns, the County's Planning and Building Department issues the permit and zones the land, the Benton-Franklin Health District permits the septic system, and the building permit will not move without proof of potable water. The RR-5 rural residential zone, with five-acre lots and room for hobby farming, is the zone built for rural homesites, alongside the county's AP-20 and AP-40 agricultural production zones. Our crews clear and grade the pad through site preparation, draw a custom plan around the shop you need, assemble the County's permit set and deliver a turnkey build. Owners with their own crew can order barndominium kits or pole barn homes and handle assembly. Before you buy acreage, tell us about it through the survey; we look up the zoning, list the water documents Franklin County will require, and estimate how much land the drainfield will take.

Franklin County at a glance

County
Franklin County
Building permit
County building department
Land use
County rural and resource zoning
Wastewater
Septic permit from the health jurisdiction
Water
Private well

Barndominium Kits and Pole Barn Homes in Franklin County

A kit suits an owner who wants to raise the shell with their own crew. A pole barn home sets its frame on posts and trusses (the engineering term is post-frame construction) and suits a wide, simple layout with a shop bay under the same roof; a metal building home uses a bolted steel frame. Which one fits your parcel comes down to the zoning, the site and the design values the local building office publishes, covered below.

Building a Barndominium in Franklin County: Permits, Zoning, Septic and Water

On rural land the zoning, septic and water answers often come before the building answer. Here is who decides each part in Franklin County, taken from the office or document that publishes it. Rules change, so check them again against your parcel before anything is drawn.

Who issues the building permit County building department

Franklin County Planning and Building Department

The County's New Residential Dwelling packet (revised June 2024) lists what a new home needs before review: plans, a sewage disposal permit signed by the Benton-Franklin Health District (which may be waived inside a sewer service area), proof of potable water and a road approach permit. Pasco and the other incorporated cities issue their own building permits, so this packet covers unincorporated land.

Source: New Residential Dwelling Application Packet, Franklin County Planning and Building (franklincountywa.gov)

Who decides the land use Rural and resource zones

Franklin County Planning Department

Each county's comprehensive plan sets rural densities under the Growth Management Act, and Franklin County's Title 17 zoning code applies them. In the RR-5 Rural Residential zone the minimum lot area is five acres with one dwelling per lot, a 35-foot height limit, and a purpose of low-density homes and hobby farms that stay self-supporting without public water and sewer.

Source: Chapter 17.16 RR-5 Rural Residential Zone, Franklin County Code (library.municode.com)

Sewer or septic Septic: local health jurisdiction

Benton-Franklin Health District

Franklin County shares its local health jurisdiction with Benton County. The Benton-Franklin Health District permits, oversees the design and installation of, and inspects household septic systems, and the County's building review expects the septic tank and drainfield on the site plan to match the location on that permit.

Source: On-Site Sewage, Benton-Franklin Health District (bfhd.wa.gov)

Where the water comes from Private well

Franklin County Planning and Building Department

Every new home needs evidence of an adequate water supply. The County's Water Availability Notification Form accepts a valid water right, a letter from a public water system that will serve the lot, a newly drilled well with its well log, or an existing well whose owner states it will supply a home within the domestic daily limit and irrigate less than half an acre.

Source: Water Availability Notification Form, Franklin County Planning and Building (franklincountywa.gov)

Code of the West
Franklin County's Code of the West warns rural buyers that water, sewer, electrical, telephone and other services may be unavailable or may not operate at urban standards, and that the county is largely agricultural, with much of the rural land actively used for crops, livestock and mineral resources.

Source: Code of the West, Franklin County (franklincountywa.gov)

Land needed for a septic system
Under the Benton-Franklin Health District's septic rules (revised 19 March 2025), a home that uses its own well needs at least one acre of land in most soil types, and two acres in the coarsest soils, while a lot served by public water can often get by with half an acre.

Source: Board of Health Rules and Regulations No. 2, Benton-Franklin Health District (bfhd.wa.gov)

Building on land near Franklin County

Rural Franklin County land ranges from five-acre RR-5 homesites to the AP-20 and AP-40 agricultural production zones. On a five-acre parcel a barndominium, a detached pole barn and a few animals fit comfortably under the zone's height and setback limits. Before you buy, confirm how you will prove potable water, since the County takes a well log, a water right or a purveyor letter but not a promise; check the soil for the septic land area; and ask how far the power line and a county road approach are. If a city lot suits you better, our Pasco page covers the City's rules.

Other places in this part of Washington

Have land in or near Franklin County? Tell us about the parcel and what you want on it, and we will check it against the local rules before anything is drawn.

Building in Franklin County: questions

Start the survey
How much does it cost to build a barndominium in Franklin County?
On rural land the site bill comes first: the well and its log, a septic system sized to the soil, the road approach, and the distance to power. After that the shell, the interior finish and the choice of a kit or a turnkey build decide the total. We price on your parcel, not an average. Sourced per-square-foot figures and what drives them are collected in our barndominium cost guide.
Do I need a building permit for a barndominium in Franklin County?
Yes. On unincorporated land the County's Planning and Building Department reviews a new home through its New Residential Dwelling packet, which also asks for the health district's septic permit and proof of potable water. Inside Pasco or another city, that city's office issues the permit. Tell us the parcel through the survey and we will confirm the office and the documents it will want.
What proof of water does Franklin County want before it issues a permit?
One of several documents: the County's Water Availability Notification Form, a well log from a licensed driller or Ecology, a health district approval for a shared well, or a paid or signed connection to a city system. An application for a water right does not count as proof on its own. We gather this with the rest of the permit set.
Can I keep animals with a barndominium on Franklin County land?
In the RR-5 zone, yes, within limits: general farming is a permitted use, and on parcels under twenty acres the code allows one animal unit for each full 10,000 square feet beyond the house's 12,000 square foot allowance, with barns and corrals set back from roads and neighbors.

Other places near Franklin County

Nearby places with their own pages. Across a city limit or a county line the permit office, the zoning, the septic program and the water rules can change, so each is covered separately.

Building in Franklin County?

Start with the survey. Tell us where the land is and what you want on it, and we will come back with which offices decide it, what the zoning allows, and a plan to fit.