Holding Tank Pumping: When Holding Tanks Are Allowed, Why They Fill and How Septage Is Handled

A holding tank has no outlet to a drain field. It stores wastewater until a pumper hauls it away, so it must be emptied on a regular interval. Washington does not allow holding tanks for residential development or expansion, with limited exceptions, and approved ones need a management program on file with the health officer.

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Last reviewed: October 26, 2026

What a holding tank is

A septic tank sends clear liquid to a drain field. A holding tank does not. It is a watertight tank with no discharge outlet that stores everything that enters it until a pumper removes the contents for treatment elsewhere. Because nothing leaves except by pumping, the tank fills at the rate water is used. A holding tank is not the same as the septic tank that sits ahead of a drain field, and it is not a cesspool, which is a bottomless tank that lets untreated wastewater into the ground.

When Washington allows one

WAC 246-272A-0240 is restrictive. A person may not install or use a holding tank sewage system for residential development or expansion of residences, whether seasonal or year-round, except as the rule sets out. The local health officer may approve installation only for permanent uses limited to controlled, part-time, commercial situations such as recreational vehicle parks and trailer dump stations; for interim uses; or for repairs as permitted under WAC 246-272A-0280.

A person proposing a holding tank must follow design criteria established by the Department of Health, submit a management program to the health officer assuring ongoing operation, monitoring and maintenance before the installation permit is issued, and use a holding tank reviewed and approved by the department. A holding tank is Option E in the failure options in WAC 246-272A-0280. It may be used only if a conforming system, a connection to sewer and a reduced-standard repair are not feasible. If none of the options works, the owner must stop using the system.

Under the rule, approved holding tanks are limited to the uses listed above. If you own property with a holding tank, ask the health district what the permit says about it.

What the management program means for pumping

SRHD adds a Spokane County requirement: holding tank systems must be inspected annually, and the owner submits a holding tank annual inspection report form to SRHD, per the holding tank agreement.

The management program is the paperwork that explains how a holding tank will be operated and monitored. In practice it tells the owner who pumps, how often, and what records go to the district. Because the rule requires it before the permit is issued, the plan is a permit document, and the owner should keep it with the other permit records. The district can say what it requires for a particular tank.

How often a holding tank is pumped

There is no single interval. A holding tank fills with every gallon of water used, so the interval depends on tank size, the number of people and fixtures, and the water use. Washington's rule does not give a number of days, and the sources used for this site do not either. The management program or the permit sets the interval for each tank. Check with the health district.

This differs from a septic tank, where the Department of Health says pumping is usually every three to five years. A holding tank is emptied of all contents each time, and pumping is the way the system disposes of wastewater.

Rules for the person who pumps

WAC 246-272A-0310 applies the same septage rules as for septic tanks. A person removing septage must obtain approval from the local health officer before removal, use vehicles clearly identified with the business name and approved by the officer, record and report septage removal as the officer requires, and dispose of septage only in a manner consistent with applicable laws. SRHD requires each Spokane County pumper to record the date, the owner or occupant name, the site address, the quantity pumped, and the date and place of disposal.

In Idaho, DEQ's definition of domestic septage includes material removed from wastewater holding tanks, RV holding tanks, portable toilets and privy vaults. Idaho pumpers hold a DEQ permit under IDAPA 58.01.03 section 050, and septage goes to a public sewer, a sewage treatment plant, or a location and method DEQ approves. Holding tanks that receive commercial or industrial waste are outside the definition.

Why the records matter

A holding tank pumped on its set interval is evidence that the system is being managed as permitted.
The pumper's record of date, quantity and disposal location is a record the district may ask for.
A record of high-water events or overflows helps the district see a pattern.
At a sale, Washington requires the seller to give the buyer all available maintenance and repair records.

Beginning February 1, 2027, Washington requires an inspection by a third-party inspector at property transfer for on-site sewage systems. Whether a local health officer treats a holding tank in a particular way is a district question. See the home sale inspection page.

Alarms and overfills

A holding tank may have a high-level alarm so that the owner knows to arrange service before the tank is full. WAC 246-272A-0240 does not itself name an alarm, so the type and setting come from the Department of Health design criteria and the permit. Ask the district or the designer how yours is set up. Never open a tank to look inside. SRHD warns that poisonous gases and a lack of oxygen can be fatal.

How to prepare

Find the permit and the management program.
Know the tank size and the date of the last pumping.
Keep a water-use log if the tank fills quickly.
Check that lids are secure. See septic risers and lids.
Ask the company for a written record each visit.

What changes the price

This site does not quote prices. A tank pumped frequently over a long haul costs more across a year than one pumped rarely, and tank size, access and distance to a disposal facility all matter. Compare the cost of pumping to the cost of the alternatives with the district, because a holding tank is generally the last option the rule allows.

Reasons to trust this page

Holding tank rules come from WAC 246-272A-0240, 0280 and 0310, SRHD and IDAPA 58.01.03.
The septage definition comes from Idaho DEQ.
No pumping interval is stated because the sources do not give one.
No company is recommended.

Frequently Asked Questions

When is a holding tank allowed in Washington?

WAC 246-272A-0240 bars holding tanks for residential development or expansion, with exceptions. The health officer may approve them for controlled, part-time commercial uses such as RV parks and dump stations, for interim uses, or for repairs allowed under WAC 246-272A-0280. A management program must be submitted first.

How often does a holding tank need to be pumped?

There is no standard interval. A holding tank has no outlet to a drain field, so it fills with water use. The permit and management program set the interval, and the health district can say what yours requires. The sources used here give no number of days.

Is a holding tank the same as a septic tank or a cesspool?

No. A septic tank sends treated liquid to a drain field. A holding tank has no discharge outlet and is emptied by pumping. A cesspool is a bottomless tank that lets untreated wastewater into the ground. Washington treats cesspools as outdated and often as failures to be abandoned and replaced.

What records should come from a holding tank pumping?

The date, owner or occupant name, site address, quantity pumped, and the date and place of disposal. SRHD requires pumpers in Spokane County to record those items, and WAC 246-272A-0310 says septage removal must be recorded and reported as the health officer requires. Keep a copy with the permit records.

Does Idaho treat holding tank waste as septage?

Yes, domestic holding tank waste. Idaho DEQ includes wastewater holding tanks, RV tanks and portable toilets in its definition of domestic septage. Idaho pumpers hold a DEQ permit, and the waste must go to a public sewer, a sewage treatment plant or an approved location and method.

Sources

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