Of more than 245,000 septic inspections filed in Pierce and King counties, 18% found a problem. Among the properties whose system type is on record — the only ones where a due date can be worked out — 51.6% have no inspection filed within their interval.
Based on inspection records filed with the Tacoma-Pierce County Health Department and King County Public Health covering more than 144,000 septic properties. Queried 28 August 2026.
The rules call it an operational evaluation, and both counties specify what it has to cover, so it is not left to the inspector's judgement. The inspector opens the tank and measures the sludge and scum in each compartment, records whether it needs pumping and how much, and checks the liquid level against the height of the outlet. They check the lids, risers, baffles and effluent filter screens, the structural integrity and water-tightness of the tank and its pipes, and whether groundwater is getting in.
If the system has a pump tank, that adds the pump itself, the float switches, the wiring and an alarm test, plus the number of pump cycles or operating hours and a drawdown test. Then the drain field: seepage, soft ground, effluent at the surface, odours, vehicle traffic, livestock, and any cut, ditch, drain or shoreline within thirty feet showing signs of effluent surfacing.
Who is allowed to sign it off differs between the two counties, and the difference is worth knowing before you book. Pierce County requires a certified operation-and-maintenance firm for every system. King County is more permissive on the simplest systems only.
| System | Pierce County | King County |
|---|---|---|
| Septic tank and gravity drain field, no pump | Certified O&M firm | The owner, a licensed maintainer, or a licensed OSS pumper |
| Pressure distribution, mound or sand filter | Certified O&M firm | Licensed maintainer |
| Proprietary treatment unit (ATU and similar) | Certified O&M firm | Licensed maintainer |
| Any system in a marine recovery area | Certified O&M firm | Licensed maintainer |
| At the time of sale | Certified O&M firm | Licensed OSM |
King County letting an owner monitor their own gravity system is the exception rather than the rule, and it does not extend to the inspection required when the property sells, to anything with a pump, or to anything in a marine recovery area. Sources: Pierce County Environmental Health Code Chapter 2, Sections 42 and 44; King County Board of Health Title 13, Table 13.60-1 and Sections 13.60.020 and 13.60.030.
Two separate rules decide this, and confusing them is the single most common mistake homeowners make. The state rule sets the inspection you must actually have done. Each county then adds its own layer on top — in Pierce, a risk classification that governs how often the result is reported to the Health Department; in King, a table of minimum monitoring frequencies by system type.
Under the state rule an on-site system consisting solely of a septic tank and a gravity drain field is inspected at least every three years, and every other kind of system every year, unless the local health officer requires it more often. That floor applies in both counties.
Solids have their own rule in King County, separate from the monitoring inspection: the owner must determine the level of solids and scum at least every three years for a residential system with no garbage grinder, every year if a garbage grinder is installed, and every year for a commercial system.
| System or event | Pierce County | King County |
|---|---|---|
| Septic tank and gravity drain field | At least every 3 years | Every 3 years |
| Pressure distribution, mound, sand filter | Every year | Every year |
| Proprietary treatment unit | Every year | Every year |
| Commercial or food establishment | Every year | Every year |
| Newly installed system, first check | On approval for use | 6 months after occupancy; 45 days for proprietary and commercial |
| In a marine recovery area | Classified moderate risk, so reported every 3 years | Not less than once a year, set by the health officer |
| When the property is sold | Report of System Status | Property transfer inspection before title transfers |
Inspection is a legal obligation, not a recommendation. How often you are due depends on what kind of system you have, though, so it can only be measured where the health department has the system type on record — and across the two counties that is 59,325 of about 144,100 septic properties. Of those, 30,631 have no inspection filed within their interval: 51.6%.
| Measure | Figure | What it covers |
|---|---|---|
| Past due for an inspection | 30,631 | Of the 59,325 whose system type is recorded |
| Share past due | 51.6% | Not of all septic households — see the note below |
| System type not recorded | 84,773 | 59% of septic properties; no due date can be worked out |
| Inspected during 2025 | 15.3% | about 22,000 households, against roughly a third a year implied by the rules |
Split by system type, the gap is not where you would expect. Gravity systems, on a three-year cycle, are 45.6% past due. Systems using pressure distribution, which the state rule puts on an annual cycle, are 70.9% past due — much the worst of the three groups, and the one whose owners are most likely to think they are on the three-year schedule. Complex and proprietary systems, also annual, are 54.8%.
Two things this figure is not. It is not a statement about every septic property: 59% have no system type on record, so no due date can be derived for them and they are excluded entirely rather than assumed compliant. And Pierce County lets eligible owner-occupied gravity systems move from a three-year cycle to a five-year one, which the filings do not show, so a few of those counted as past due are legitimately on the longer cadence.
The strongest signal of whether an inspection turns something up is not the age of the system or where it sits. It is why the inspector was there in the first place.
| Why the inspector was there | Inspections | Found a problem |
|---|---|---|
| Complaint | 491 | 45.8% |
| Property sale | 90,022 | 19.2% |
| Routine operation and maintenance | 106,365 | 17.4% |
| Follow-up | 19,120 | 12.1% |
| New system startup | 335 | 2.7% |
Two further patterns sit in the same records. A partial inspection finds a deficiency 22.3% of the time against 16.4% for a full one, across more than 55,000 partial records — so the cheaper, narrower visit is the one more likely to surface something, which is worth knowing when a quote offers you the choice. And history matters: of inspections following a previous pass, 17.0% find a problem; of those following a previous deficiency, 29.4% do.
The third pattern is the condition systems are found in when the gap has been long.
| Time since the last inspection | Inspections | Found a problem |
|---|---|---|
| On schedule (1.5 to 3.5 years) | 29,657 | 16.7% |
| Lapsed six years or more | 11,770 | 19.2% |
| First inspection on record | 42,447 | 21.3% |
That last table describes the condition systems are found in, not proof that inspecting prevents problems. A longer gap is also simply more time in which something could have gone wrong. What it does show is that a first-ever inspection is the one most likely to turn something up, which matters if you have just bought a house and no record exists for it.
Washington requires an inspection when a property on septic changes hands, whatever the system type. In Pierce County that is a Report of System Status; in King County a property transfer monitoring and performance inspection filed by a licensed OSM before title transfers, which is waived only if one was done in the previous twelve months and the property has not changed hands since. Because nobody can skip it, the point-of-sale records are a complete census of a defined event rather than a sample — and the direction of travel is not good.
| Year | Sale inspections | Found a problem |
|---|---|---|
| 2018 | 9,009 | 17.9% |
| 2024 | 6,297 | 24.9% |
The other thing the records show a seller is when to book. Routine inspections are close to seasonally flat, peaking in October with a 1.38× swing between the busiest and quietest months. Sale inspections are nothing like flat: they peak in May and bottom out in December, a 2.45× swing that simply tracks the housing market.
| Inspection type | Peak month | Quietest | Swing |
|---|---|---|---|
| Routine operation and maintenance | October | Flat year round | 1.38× |
| Property sale | May | December | 2.45× |
If you are listing in spring you are competing for the same inspection capacity as every other seller in the county. Booking before you list, rather than once you are under contract, is the difference between a finding you have time to deal with and one that lands in the middle of a closing.
First, the word. A deficiency is an inspection filed with a status of Deficient, and the records carry no severity field — it covers everything from a missing riser lid to a failed drain field. It is not the same thing as a broken system, and most are not emergencies.
Of the deficiencies filed between 2015 and 2024, 77.8% are eventually recorded as resolved. Only 50.3% are resolved within a year, and 22.2% have no resolution on record at all. The spread of how long it takes is wide enough to matter.
| Percentile | Days to a confirmed fix | In plain terms |
|---|---|---|
| 25th | 14 | Sorted inside a fortnight |
| 50th | 131 | About four months |
| 75th | 651 | Nearly two years |
| 90th | 1,395 | Almost four years |
For anyone thinking about selling, that 75th percentile is the number to look at: a quarter of septic problems take more than eighteen months to close out. That is the argument for inspecting well before you list rather than at closing — not because the repair itself takes two years, but because scheduling, permitting and design on the more involved jobs are not things you can compress once a buyer is waiting.
Our septic inspection is a flat $299, and that price includes the health department's filing fee for lodging the report. It is not a starting price, and it does not change with the size of your tank or how far out you are.
If the inspection finds something and you decide to go ahead with the repair, we will often reduce the initial inspection fee and bundle it into the cost of the repair work.
One thing does sit outside it. If the tank needs pumping — which the inspection will tell you — that is a separate job, at a flat $549 plus tax for up to 1,200 gallons.
| Service | Price |
|---|---|
| Septic inspection, including the filing fee | $299 flat |
| Septic pumping, up to 1,200 gallons | $549 flat, plus tax |
We hold no data on what other companies charge, and the health department records contain no pricing, so there is no regional average on this page. The figures above are ours.
Past-due rates run from 27.7% to 65.9% across the 45 towns — but read the second column first. A due date can only be worked out where the system type is on record, and how consistently that got recorded differs sharply between the two counties: a median of 69% of households in the King County towns, against 13% in the Pierce ones. Sorted by the share past due.
| Town | County | System type on record | Past due | Past twice the interval |
|---|---|---|---|---|
| Black Diamond | King | 464 of 720 | 65.9% | 41.8% |
| North Bend | King | 1,865 of 2,354 | 65.7% | 45.8% |
| Anderson Island | Pierce | 51 of 831 | 64.7% | 45.1% |
| Graham | Pierce | 702 of 7,118 | 64.2% | 43.6% |
| Ravensdale | King | 586 of 868 | 63.7% | 37.7% |
| Fall City | King | 836 of 1,076 | 62.3% | 39.6% |
| Snoqualmie | King | 329 of 429 | 61.7% | 44.7% |
| Enumclaw | King | 1,622 of 2,584 | 60.3% | 36.3% |
| Spanaway | Pierce | 714 of 7,048 | 60.2% | 38.7% |
| Carnation | King | 948 of 1,268 | 59.7% | 40.4% |
| Roy | Pierce | 299 of 3,427 | 58.5% | 37.5% |
| Renton | King | 3,281 of 4,616 | 57.1% | 35.5% |
| Vashon | King | 2,101 of 3,367 | 56.3% | 33.7% |
| Maple Valley | King | 1,867 of 2,641 | 55.8% | 35.0% |
| Orting | Pierce | 196 of 1,716 | 55.1% | 35.2% |
| Buckley | Pierce | 382 of 3,217 | 55.0% | 32.7% |
| Redmond | King | 2,752 of 3,761 | 55.0% | 32.7% |
| Duvall | King | 726 of 1,045 | 54.3% | 34.8% |
| Covington | King | 786 of 1,185 | 54.2% | 28.8% |
| Kent | King | 2,713 of 4,121 | 54.2% | 30.9% |
| Puyallup | Pierce | 424 of 2,660 | 53.8% | 31.6% |
| Eatonville | Pierce | 244 of 2,461 | 53.7% | 34.4% |
| South Hill | Pierce | 1,209 of 10,115 | 53.6% | 30.6% |
| Issaquah | King | 1,836 of 2,418 | 52.7% | 31.3% |
| Auburn | King | 3,790 of 5,841 | 52.5% | 27.9% |
| Fox Island | Pierce | 798 of 1,473 | 51.3% | 30.2% |
| Lakewood | Pierce | 104 of 1,032 | 51.0% | 36.5% |
| Bonney Lake | Pierce | 752 of 5,618 | 50.4% | 30.9% |
| Seattle | King | 770 of 1,103 | 50.4% | 29.2% |
| Burien | King | 962 of 1,524 | 50.2% | 27.3% |
| Sammamish | King | 1,805 of 2,426 | 49.7% | 30.5% |
| Kirkland | King | 553 of 911 | 49.5% | 29.7% |
| Bellevue | King | 763 of 1,076 | 49.3% | 27.8% |
| Federal Way | King | 1,793 of 2,865 | 48.7% | 23.8% |
| University Place | Pierce | 279 of 1,469 | 48.4% | 24.7% |
| Des Moines | King | 404 of 609 | 48.0% | 23.3% |
| Woodinville | King | 4,331 of 6,385 | 47.7% | 27.5% |
| Gig Harbor | Pierce | 9,047 of 16,738 | 46.0% | 23.6% |
| Sumner | Pierce | 68 of 483 | 45.6% | 14.7% |
| Tacoma | Pierce | 1,056 of 8,003 | 42.8% | 22.8% |
| Edgewood | Pierce | 493 of 3,210 | 41.4% | 20.1% |
| Lake Tapps | Pierce | 634 of 4,201 | 33.8% | 16.2% |
| Vaughn | Pierce | 315 of 569 | 32.4% | 13.3% |
| Lakebay | Pierce | 1,267 of 2,377 | 27.9% | 11.1% |
| Longbranch | Pierce | 358 of 581 | 27.7% | 9.8% |
Because of that second column, this is partly a table of record-keeping and not only of behaviour. Sixteen towns — every one of them in Pierce County — have a system type on record for under a quarter of their septic properties, and on Anderson Island it is 51 properties out of 831. Those percentages describe a small, self-selected group and should not be read as a verdict on the town.
The clearest pattern that does survive is at the bottom of the table. The four most compliant places are Longbranch, Lakebay and Vaughn on the Key Peninsula, and Lake Tapps — between 27.7% and 33.8% past due, against a regional 51.6%. The Key Peninsula is the one part of Pierce County the Health Department has designated an area of special concern, which puts systems there on a tighter reporting cycle, and all three towns have a far better recorded share than the rest of the county. That is a pattern in the records rather than a demonstrated cause, but it is a consistent one.
We are a certified operation-and-maintenance firm in both counties, so an inspection we carry out is one that can be filed. Every inspection is done by one of our certified technicians, who will walk you through what they found and, if there is a problem, set out your options and what each one costs before you decide anything.
Upfront Septic & Plumbing is built on reliability, transparency, and quality service. We show up when we say we will, explain the work clearly, and provide honest pricing. Our goal is to deliver long term solutions, not quick fixes.
We take pride in serving local communities and building lasting relationships with our customers through dependable service and professional results.
If you need septic pumping, plumbing services, or 24 hour emergency septic service, Upfront Septic & Plumbing is ready to help. Contact us today to schedule service, request an inspection, or get immediate assistance.
If your system is a septic tank with a gravity drain field, at least every three years. Anything more complex — pressure distribution, a mound, a sand filter, or a proprietary treatment unit — is every year. That is the state rule and it applies in both Pierce and King County. Pierce adds a risk classification that decides how often the result is reported to the Health Department, and King sets its own minimum frequencies in Table 13.60-1, but the inspection itself is on the three-year or annual cycle either way.
In King County, on a gravity system without a pump, yes — the code allows the owner, a licensed maintainer or a licensed OSS pumper to perform the routine monitoring. Anything with a pump, anything in a marine recovery area, and the inspection required when you sell all need a licensed professional. In Pierce County the answer is no: the operational evaluation has to be carried out and reported by a certified operation-and-maintenance firm, whatever the system type.
Yes, in both counties, and regardless of what kind of system you have. In Pierce County you apply for a Report of System Status. In King County the seller must have a property transfer monitoring and performance inspection carried out by a licensed OSM before title transfers — unless one was already done in the previous twelve months and the property has not changed hands since. King County also requires the owner to hand the buyer the maintenance records if they have them.
A full inspection covers the whole system; a partial one covers only part of it. It matters more than it sounds. Across more than 55,000 partial inspections filed in the two counties, 22.3% found a deficiency, against 16.4% of full inspections — so the narrower visit is the one more likely to surface a problem, not less. If a quote offers you the choice, that is the context for it.
Ours is a flat $299, and that includes the health department's filing fee for lodging the report — there is no separate county charge on top. If we find something and you decide to go ahead with the repair, we will often reduce that initial inspection fee and bundle it into the repair cost. We do not hold data on what other companies charge, so there is no regional average on this page.
An inspection filed as deficient is not the same as a broken system — the records carry no severity field, so a deficiency covers anything from a missing riser lid to a failed drain field. You are responsible for the timely repair, and the fix is confirmed by a follow-up filing. Of the deficiencies filed between 2015 and 2024, 77.8% were eventually recorded as resolved, about half within a year.
Sludge and scum levels in each compartment of the tank, whether it needs pumping and how much, the liquid level against the outlet, the lids, risers, baffles and filter screens, and whether the tank and its pipes are sound and watertight. On a system with a pump, also the pump, floats, wiring, alarm, cycle counts and a drawdown test. Then the drain field: soft ground, surfacing effluent, odours, vehicle or livestock traffic, and any ditch, drain or shoreline within thirty feet showing effluent at the surface.
For a sale in King County, an inspection performed within the previous twelve months satisfies the transfer requirement provided the property has not changed hands since. In Pierce County a Report of System Status is issued on an inspection up to six months old, and once issued the RSS is valid for twelve months and cannot be renewed.
It is common. Among the properties in the two counties whose system type is on record, about half — 51.6% — have no inspection filed within their interval. It is also the situation most likely to turn something up: first-ever inspections find a deficiency 21.3% of the time, against 16.7% for systems inspected on schedule. That is partly just accumulated time rather than neglect, but if you have recently bought a house with no record on it, that is the number to know.
About this analysis. Washington requires every on-site septic system to be inspected on a recurring cycle: at least every three years for a septic tank with a gravity drain field, and every year for anything more complex. Each county adds to that. King County sets its own minimum monitoring frequencies by system type, and Pierce County assigns each system a risk classification that sets how often the result must be reported to the health department. The inspection must be filed with the health department, and those filings are public records.
This analysis covers more than 245,000 inspections across upwards of 144,000 septic properties in Pierce and King counties, as recorded by the Tacoma-Pierce County Health Department and King County Public Health. Because inspection is mandatory rather than voluntary, this is a near-complete record of professional septic service in both counties rather than a survey sample: there is no response bias and nothing is self-reported by homeowners.
Definitions. A deficiency is an inspection filed with a status of Deficient; severity is not recorded, so a deficiency may be anything from a missing riser lid to a failed drain field. A failure rate is deficiencies as a share of inspections filed, not of properties, which avoids bias from properties observed over different lengths of time. Past due means no inspection on file within the interval that property's system type calls for.
The limits on the past-due figures. A due date depends on the system type, so these cover only the 59,325 properties where the type is recorded — 41% of the total. The other 84,773 are excluded rather than assumed compliant, and the recorded share is far higher in King County than in Pierce, so comparisons between towns in different counties carry that difference with them. Separately, Pierce County's reduced-frequency programme moves eligible owner-occupied gravity systems from a three-year cycle to a five-year one and approvals are not visible in the filings, so a share of those counted as past due are legitimately on the longer cadence. An earlier cut of this analysis also placed pressure-distribution systems on the three-year cycle; the state rule puts them on an annual one, and correcting it moved 4,036 households into the past-due count.
Scope and limits. Inspection figures cover 2015 to 2025; deficiency resolution covers 2015 to 2024; the record was queried on 28 August 2026 and the underlying pipeline is live, so counts drift. Individual property owners are not identified, and no figure here describes any single company's results.
A Tacoma tank that had gone a long time without being pumped. The customer had opened the first compartment; we excavated the second to reach the whole tank, crust busted through a heavy build-up of solids, and pumped approximately 1,125 gallons — a job that took considerably longer than usual because of the condition inside.
A two-compartment tank in University Place with risers on every access point but the outlet. The transport line at the outlet was completely submerged, pointing at a drainfield beginning to struggle, and root intrusion was found where the risers meet the tank. We pumped approximately 1,125 gallons and stress tested the system.
An inspection and pump assessment on Anderson Island. The drawdown test came in at about 0.75 inches per minute against roughly 1 expected, and the pump tank showed massive root intrusion. Risers were recommended on all tanks.
A high-level alarm at a Gig Harbor property with the pump tank flooded. We pumped the pump tank and about 1,125 gallons from the septic tank, and the inspection found a pump that would not activate, an unsealed junction box, root intrusion and lid damage.
A camera inspection checked the drain field against the property's as-built drawing, confirming five lateral lines running almost to the fence. We opened the valves for even dispersal, pumped the tank and pump basin, and replaced the tank lids.
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