How Often Should You Pump a Septic Tank in Oklahoma?
In Oklahoma, plan on pumping a septic tank every three to five years under average conditions. That range comes from the Oklahoma Department of Environmental Quality (DEQ), which runs the state’s septic program. The EPA gives the same range for household tanks.
Your own number turns on how many people use the tank and how big it is. The DEQ’s chart gives two people on a 1,000 gallon tank about six years between pumpings. A family of four on the same tank needs pumping about every three years.
When your tank is due, septic tank pumping takes the solids out before they reach the lateral lines. Those lines, also called the drain field, let the water soak into the soil.
How often does a septic tank need pumping by household size?
Extension service guides publish a table of pumping intervals by tank size and household size. The numbers below are its estimated years between pumpings, for homes lived in all year. The table’s note adds that a home with a garbage disposal needs pumping more often.
| People in the home | 750 gallons | 1,000 gallons | 1,250 gallons | 1,500 gallons |
|---|---|---|---|---|
| 1 | 9.1 | 12.4 | 15.6 | 18.9 |
| 2 | 4.2 | 5.9 | 7.5 | 9.1 |
| 3 | 2.6 | 3.7 | 4.8 | 5.9 |
| 4 | 1.8 | 2.6 | 3.4 | 4.2 |
| 5 | 1.3 | 2.0 | 2.6 | 3.3 |
| 6 | 1.0 | 1.5 | 2.0 | 2.6 |
Oklahoma’s septic rules (OAC 252:641) call for at least a 1,000 gallon tank on homes with up to four bedrooms. Each bedroom past four adds 250 gallons, so five bedrooms call for at least 1,250 and six for 1,500. One extension guide notes that older systems may have smaller tanks than today’s rules require.
The DEQ’s homeowner guide charts a 1,000 gallon tank in whole years. It lists 12 years for one person, 6 for two, 3 for four, 2 for six and 1 for eight. The guide says its chart should not take the place of a professional inspection or a measurement of the sludge.
How do you know when a septic tank is full?
The DEQ guide sets its pumping marks by the sludge, the solids that settle to the bottom of the tank. It says to pump when sludge reaches 40 percent of the tank’s depth, about 25 inches on a pole. It also calls for pumping when sludge and scum together fill a third or more of the liquid depth.
The DEQ guide shows how to check the sludge yourself with a six-foot rod. Work from outside the tank, because an extension guide says to never enter one.
Your drains and your yard also give warning signs. The EPA and the DEQ name these:
- Sewage backing up into toilets and sinks
- Tubs and showers that drain very slowly
- Gurgling sounds in the drains
- Sewage smells inside the house or out in the yard
- Damp spots or bright green, spongy grass over the tank or the lines, even in dry weather
- Sewage coming up in the yard
For backups, slow drains, odors and sewage in the yard, the DEQ guide lists pumping the tank among the fixes. It also names other causes, such as roots in the pipes and too much water going in. Soggy ground over the lines can mean the lines themselves are in trouble. Our guide covers the signs of failing lateral lines in Oklahoma clay.
If pumping does not clear the trouble, we find the cause on site. Any septic system repair gets a written quote before the work starts.
What makes a septic tank fill faster?
The EPA names four things that set how often a tank needs pumping. They are household size, the total wastewater, the solids in that water and the size of the tank. You can change two of them, the water and the solids, with daily habits.
Start with the garbage disposal. The DEQ guide says food waste can fill a tank quickly. With a disposal, it says to size the tank 20 percent larger and pump every one to two years.
Water matters because solids need time to settle. The DEQ guide says settling takes about a day, and a rush of water cuts that time short. Spread laundry over several days instead of running many loads in one day.
Fix leaks, too. The EPA says one running toilet can add as much as 200 gallons a day. Oklahoma’s extension service notes that visitors can double a home’s daily water use.
The tank’s bacteria cannot readily break down some things, so they stay in the tank. The DEQ guide’s do-not-flush list includes paper towels, disposable diapers, cat litter, grease, cooking oil and coffee grounds. The EPA adds baby wipes and other wet wipes.
How often does an aerobic septic tank need pumping?
An aerobic system starts with a trash tank, where solids settle out. The water then moves on to the aeration tank and, on a spray system, out to the spray heads.
Oklahoma’s extension service says to check the solids in the trash tank at least every six months. It says to pump when the sludge reaches 40 percent of the tank’s liquid capacity. For the aeration tank, it says to follow the maker’s method for testing sludge.
Oklahoma’s septic rules make the installer maintain a new aerobic system for its first two years. That includes measuring the sludge in the trash tank at least every six months. After that, the owner keeps up the system or hires someone to do it.
The EPA says systems with pumps and float switches should be inspected more often, generally once a year. An aerobic system runs an air pump, so it falls in that group. Regular aerobic septic system maintenance puts those checks on a schedule. We pump the tanks on aerobic systems as well as conventional tanks.
What does the pumper check while the tank is open?
The DEQ guide says to have all of the contents pumped out. Extension guides say to pump through the large center opening, not the small ports over the baffles. Pumping through those small ports can damage the baffles.
Baffles hold the sludge and scum in the tank, so they get checked before the lid closes. The EPA says the service provider also checks for leaks and looks at the scum and sludge layers. The provider should note the tank’s condition and any repairs in a service report.
When we pump a tank, we check the tank and its baffles while it is open. Then we tell you what we see, in plain words.
Keep a record of every pumping. The DEQ guide has a maintenance record page with lines for the tank size and each visit. The EPA says to write down the sludge and scum levels too, so you can time the next pumping.
When should you schedule septic tank pumping?
Check the date of your last pumping against the table above. If your tank is past due, or you cannot find a date, have it checked. The DEQ guide says to have a septic tank inspected every year. The EPA calls spring a great time to service a septic system.
Eastern Oklahoma Septic Services pumps conventional septic tanks and the tanks on aerobic systems. We are based in Sapulpa and work about 40 miles around it, across the Tulsa area. Call or text (918) 645-0557 about septic tank cleaning around Sapulpa, and we put the quote in writing.