How are homes with septic and a private well appraised in California?

Who sets the septic and well rules in California?

Septic systems in California fall under the State Water Resources Control Board's Onsite Wastewater Treatment Systems Policy, called the OWTS Policy. It grew out of a 2000 law, AB 885, and went into effect May 13, 2013. The State Water Board estimates California has over 1 million of these systems.

The policy works in tiers based on risk. Most working systems that already exist sit in the lowest tier. Day to day, your county environmental health department is the one issuing permits. Many counties run their own Local Agency Management Program, a local rulebook approved by the Regional Water Board.

The policy says owners have to maintain their systems, with inspections and pumping as needed or as local rules require. It does not create a statewide inspection at sale. Some counties do. Santa Cruz County, for example, has required sellers since July 1, 2023 to have the septic system professionally pumped and inspected and to give buyers a disclosure. Needed repairs fall on the seller unless the buyer and seller agree otherwise.

Your county may have its own version, or nothing at all. Call county environmental health before you list. It is a short call, and nobody at that office has ever been surprised by a septic question.

What lenders and the appraiser have to check

Loan rules decide whether the house qualifies. The market decides what it is worth. Here are the rules I can point to:

• Fannie Mae says utilities must meet community standards. A private well or septic system has to sit on the subject property, unless the owner has a legal, binding agreement to use and maintain one off site. If buyers resist an area because of problems that affect wells or septic, the appraisal must address the effect on value and marketability.
• FHA lists minimum distances for an existing home's well: 10 feet from the property line, 50 feet from the septic tank and 100 feet from the drain field. If the local rule is stricter, the local rule wins. The lender must make sure the well water meets the local health authority's standards, or the EPA's where there are none.
• USDA always requires a safe water test for a private well. I cover that in USDA appraisal requirements.

HUD has also posted a draft rewrite of its property standards, so FHA details may change. Check the current handbook before you plan around a number.

The appraiser is not a septic inspector and does not test water. I look for visible trouble, like soggy ground or odors, and I report what I see. A suspiciously green stripe of lawn in August is not a gardening win.

Drought, well depth and the records worth pulling

A well is only as good as the water under it. In dry years that becomes a real buyer question, not a trivia question.

The California Department of Water Resources keeps an online index of Well Completion Reports filed by drillers. A record can include the well's total completed depth. DWR warns that the data has missing and wrong values, and most locations are only placed at the center of a one square mile section. Use it as a lead, then find the actual report for your well.

DWR also runs the Dry Well Reporting System, set up in early 2014 during an earlier drought. Households report water shortages from private wells, and the reports help state and local agencies see how drought hits household water.

What a buyer should ask for:

• The well log or completion report, if the seller has it
• A recent flow test from a well contractor
• A water quality test from a certified lab
• Septic pumping and service records, plus a map of the tank and leach field

A seller who hands over a folder like that looks like someone with nothing to hide. A seller who says "the water tastes fine" looks like someone who has never tested it.

How I pick comps for a septic and well home

Fannie Mae says comparable sales (recent sales of similar homes) should have similar physical and legal features to the subject. Utilities are part of that. A house on city water and sewer may appeal to a different buyer than a house where the owner is the water company.

My first choice is sales with the same setup in the same market area. Out in the rural parts of a county, every recent sale on the road may share the same setup, and the utilities are simply normal. When everyone has septic, buyers do not pay less for it. That is a zero adjustment, and it is earned by the data.

The harder case is a septic and well home sitting at the edge of town, next to homes on public utilities. Say, hypothetically, two similar homes sold a month apart, one on sewer and one on septic. The price gap, after adjusting for every other difference, is evidence of what buyers paid for the hookup. One pair is a story. Several pairs that agree are a rate.

When matching sales are thin, I go back in time before I go farther away. An older sale with the same utilities, adjusted to today's market, often tells me more than a fresh sale on city sewer. More on that in how far away comps can be.

What I see in the field

Facts over feelings. The two feelings I hear most are "septic always kills value" and "septic doesn't matter at all." Both are guesses. The sales decide.

The thing that does move value is a system that is not working. A failing leach field or a well that runs dry is not a utility difference. It is a condition problem with a repair bill attached, and buyers price it that way. That gets measured and explained, not folded quietly into the location line.

I also see a lot of confusion on manufactured homes on acreage, where well, septic and land all carry the value together. If that is your property, read how a manufactured home on land is appraised.

Checklist before you list or buy

1. Call county environmental health and ask whether a septic inspection or pumping is required at sale.
2. Find the tank and leach field. Get the permit file or a site map from the county if you can.
3. Pull the well records: completion report, recent flow test and a water quality test.
4. Ask the loan officer early which program applies. FHA, USDA and conventional loans treat wells differently.
5. Check for shared wells or off-site systems and make sure a written, recorded agreement exists.
6. Give the appraiser access to the well head, pressure tank and any septic lids.
7. Hand over the folder. Dates, costs and service records beat "it works great."

For a property outside a loan, such as an estate or a family buyout, a private appraisal follows the same evidence without the lender checklist.