Septic Inspections Anderson Island

Every septic inspection in Pierce County is filed with the health department, so what follows is what inspectors actually recorded in Anderson Island rather than a rule of thumb.

Of the inspections filed in Anderson Island over the decade to 2025, 7.9% recorded a deficiency — 7.8 points below the Pierce County average. A deficiency is an inspection filed with a status of Deficient, and the records carry no severity field, so it covers everything from a missing riser lid to a failed drain field. It is not the same thing as a broken system.

Roughly 53% of the inspections here happened because a property was changing hands, and 7.3% of those found something. Washington requires an inspection at sale whatever the system type, so that group is a complete count of a defined event rather than a sample.

How often you are due depends on what kind of system you have, so this can only be measured where the type is on record. On Anderson Island that is 51 of the 831 septic properties — 6%. Of those, 64.7% have no inspection filed within their interval and 45.1% are past twice it. The rest cannot be assessed either way, and nothing here should be read as a finding about them.

That recorded share is low, so treat the percentage as indicative rather than precise: it describes 51 properties, not the whole of Anderson Island, and there is no reason to assume the unrecorded majority behave the same way.

One further caveat. Pierce County allows eligible owner-occupied gravity systems to move from a three-year cycle to a five-year one, and approvals are not visible in the filings, so some properties counted here as past due are legitimately on the longer cadence.

If you do not know where your own system stands, we can tell you: there is more on what an inspection covers, who is allowed to carry one out and what the records show region-wide on our septic inspections page.

Two rules stack, and the difference matters. The state rule sets the inspection you must actually have done: at least every three years for a system that is just a septic tank and a gravity drain field, and every year for anything more complex, unless the Health Department requires it more often.

The Tacoma-Pierce County Health Department then assigns your system a risk classification, which sets how often the result must be reported to them: annually at high risk, every three years at moderate risk, and at low risk only when you apply for a Report of System Status, after a new system is installed, or when the Health Department asks. Gravity and pump-to-gravity systems are generally low risk; pressure distribution, mounds and sand filters are moderate; holding tanks and community systems are high. Age, repair history and drainage toward sensitive water can raise the tier, and the Health Department notifies you in writing ahead of the due date.

In Anderson Island, as everywhere in Pierce County, the evaluation has to be carried out and reported by a certified operation-and-maintenance firm — there is no homeowner option. Owner-occupied gravity systems can apply to move a three-year cycle to five if they meet every condition, one of which is that the property is not on a shoreline. Selling triggers a Report of System Status.

Sources: WAC 246-272A-0270(1)(e); Pierce County Environmental Health Code Chapter 2, Sections 34, 38, 39, 42 and 44. Operation and maintenance · Reduced inspection frequency