Sourced from the Yakima Health District’s on-site sewage system pages, its published Site and Soil Evaluation and Existing System Evaluation procedures, and chapter 246-272A WAC — last checked August 2026. Where we could not source something, we say so.
Quick answer: Yakima is the county that is already doing the 2027 inspection. Its Mortgage Review, which the district itself also calls a Property Transfer Inspection, is an existing service you can book today — it is simply optional. The district states plainly: “Starting February 1, 2027, a Property Transfer Inspection will be required for the sale of any property with a septic system.” The machinery is built. Only the word “optional” changes.
First question: are you even allowed a septic system?
Before anything else, Yakima asks you to check whether a septic system is permitted on the parcel at all. The county’s rule is a distance test:
If your property is within 200 feet of a public sewer line and service is available, or if it sits within a city utility service area, you may be required to connect to sewer instead of installing a septic system.
There is a wrinkle here that does not exist in most of Washington. Sewer service in Yakima County may be provided by a county, a city, or a Yakama Nation system, and the county tells you to contact the sewer operator directly for availability and connection requirements. Which operator serves your parcel is not obvious from a map, and it decides whether the rest of this page applies to you at all.
This is the single most expensive thing to get wrong here. A failed system 180 feet from a main is not a repair project — it is a connection project, at a very different price.
The 2027 inspection already exists here
Most Washington counties are silent about the statewide change. A few name the date. Yakima is the only one we have found that already runs the service.
The district offers a Mortgage Review, and its own page adds the parenthetical: “also called a Property Transfer Inspection.” It verifies the condition of existing water and wastewater systems for a real estate transaction. District staff review available records and may conduct an on-site inspection, depending on the property and the lender’s requirements.
Today it is voluntary. In the district’s words, mortgage reviews “are not required by law, but are commonly requested by lenders” as part of a home sale or refinancing. Then comes the notice:
“Starting February 1, 2027, a Property Transfer Inspection will be required for the sale of any property with a septic system.”
For a seller, that is unusually good news, and it is worth being clear about why. Elsewhere in Washington the 2027 problem is that nobody knows who will be allowed to inspect or what form they will use. In Yakima the service, the application, the checklist and the property owner’s statement all already exist. If you want to know today what a 2027 sale will involve here, you can simply book one.
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Three different reviews, and they are not interchangeable
Yakima runs three separate property review services that people routinely confuse. Asking for the wrong one costs time.
| Review | When you need it |
|---|---|
| Septic Clearance | Part of a building permit when you are changing the property — a home addition, a storage shed, a pool. It checks whether the project interferes with the tank or drainfield, whether setbacks are maintained, whether the system has capacity for the change, and whether an existing system can serve a new or replacement residence. |
| Existing System Evaluation | When nobody knows what is down there. Used where there is no record of the system, where it predates record-keeping or was installed without a permit, where a building is being expanded and the records are missing, or where a lender or buyer needs proof the system meets current requirements and no record can be found. It determines the size, type, layout and location of what exists. |
| Mortgage Review | The property transfer inspection described above. Optional today, required from February 1, 2027. |
The middle one is the one to think about early if you are buying an older rural property. If the district has no record of the system, an Existing System Evaluation is what turns an unknown into a documented asset — and it is far better to discover that gap during a purchase than during a sale.
Building a new system
Assuming sewer connection is not required, the district publishes a six-step sequence:
| Step | What it involves |
|---|---|
| 1 | Apply for a site and soil evaluation and dig test holes |
| 2 | Hire a licensed septic system designer |
| 3 | Apply for the on-site septic system permit |
| 4 | Design review and permit approval |
| 5 | Install the system and submit the as-built record |
| 6 | Final inspection and approval |
What determines the system you end up with is soil depth, soil type, slope and setbacks. Soil depth decides what can safely be installed, soil type decides how large it must be, and slope and setbacks limit where it can go — or force a different type entirely.
The four feet that decide your budget
The district’s site and soil evaluation procedure contains the number that matters most to anyone buying land here:
A gravity flow septic system requires a minimum of four feet of suitable soil, with a three-foot separation between the bottom of the drainfield trench and an impermeable layer or groundwater. A site with less than four feet of soil requires an alternative system — and alternative systems cost substantially more to build and to maintain. Sites with slopes over 15 percent may need deeper soil still for gravity to work.
That single threshold is the difference between the cheapest system available and an engineered one, and you find out which side of it you are on at the site evaluation — before you have committed to a design.
Digging the test holes
The soil information gathered from the test holes is the soil log, and it drives the location, type and size of the system plus the replacement area. The district’s requirements:
| Requirement | Detail |
|---|---|
| Number | A minimum of two test holes for the proposed drainfield and two for the replacement area. Some sites need more. |
| Spacing | Approximately 75 to 100 feet apart |
| Depth | 6 feet, with 8 feet the maximum. Stop shallower if hardpan, bedrock or groundwater is hit. |
| Width | At least 2 feet wide, so field staff can observe soil texture, structure, color and compaction |
| Access | Angle one end of the hole with a landing at the 4-foot level for staff access |
District field staff will advise on where to place them, which is worth taking up before you hire the excavator rather than after.
What we could not source
- 🔴 Any fee schedule. We could not find published prices for the site and soil evaluation, the septic permit, the septic clearance, the existing system evaluation or the mortgage review. The county’s applications and resources page returned an error when we checked. Call the help desk before budgeting.
- Whether the Mortgage Review as it exists today will satisfy the 2027 requirement unchanged, or whether the form and scope will be revised to match the state rule.
- Who will be authorized to perform the required inspection from 2027 — district staff, licensed professionals, or both.
- A published map of sewer service areas, including which parcels fall within a Yakama Nation system’s service area. The district directs you to contact the operator instead.
- How many on-site systems are in the county. Not published anywhere we could find.
The practical bits
| Yakima Health District — Environmental Health Help Desk | 1210 Ahtanum Ridge Drive, Union Gap, WA |
| Phone | (509) 249-6508 |
| YHD.HelpDesk@co.yakima.wa.us | |
| Mortgage review paperwork | Process instructions, application, checklist, and a property owner’s statement are all published |
Sources
- Yakima Health District, Septic Systems — yakimacounty.us
- Yakima Health District, Building a New Septic System — yakimacounty.us
- Yakima Health District, Septic System Property Reviews — yakimacounty.us
- Yakima Health District, On-site Sewage System Program — Site and Soil Evaluation procedure — yakimacounty.us
- WAC 246-272A-0270, including the property transfer provisions effective February 1, 2027
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Frequently Asked Questions
Will Yakima County require a septic inspection when I sell my house?
Yes, from February 1, 2027. The Yakima Health District states that starting February 1, 2027 a Property Transfer Inspection will be required for the sale of any property with a septic system. Unusually, the district already offers that inspection today as an optional service called a Mortgage Review, which its own pages also call a Property Transfer Inspection. It is currently not required by law but is commonly requested by lenders, so the process, application and checklist already exist.
Can I install a septic system if there is a sewer line nearby in Yakima County?
Maybe not. If your property is within 200 feet of a public sewer line and service is available, or if it is inside a city utility service area, you may be required to connect to sewer instead of installing a septic system. Sewer may be provided by a county, city, or Yakama Nation system, and the district tells you to contact the sewer operator directly about availability and connection requirements. Check this before anything else, because it changes the entire cost of the project.
How much soil do I need for a gravity septic system in Yakima County?
At least four feet of suitable soil, with a three foot separation between the bottom of the drainfield trench and an impermeable layer or groundwater. A site with less than four feet of soil requires an alternative system, which costs substantially more to build and maintain. Sites with slopes over 15 percent may require deeper soil for a gravity system.
What is the difference between a septic clearance, an existing system evaluation and a mortgage review in Yakima County?
A septic clearance is part of a building permit when you change the property, such as an addition, shed or pool, and checks interference, setbacks and capacity. An existing system evaluation determines the size, type, layout and location of a system when there are no records, when it predates record keeping or was unpermitted, or when a lender needs proof and no record exists. A mortgage review, also called a property transfer inspection, verifies the condition of existing water and wastewater systems for a real estate transaction.