What are the signs that your septic tank is full?
The US EPA's homeowner guide lists four failure symptoms: wastewater backing up into household drains, bright green and spongy grass on the drainfield even during dry weather, pooling water or muddy soil around the system or in the basement, and a strong odor around the tank and drainfield. It also warns that a foul odor is not always the first sign. In the order most people notice them:
1. Slow drains everywhere. One slow sink is a branch clog. Slow sinks, tubs and toilets together mean the whole line is struggling to move wastewater into the tank.
2. Gurgling. Bubbling or glugging in a toilet or drain, especially when another fixture empties, means the plumbing is not moving water the way it should.
3. Odor. A sewage smell in the house, in the garage or over the tank lid means gas is getting out somewhere it should not.
4. Wet or unusually green ground. Grass that stays soggy, or turns lusher and greener than the rest of the lawn during dry weather, over the tank or the drain field, is the EPA's own warning sign.
5. Sewage at the lowest fixture. A basement floor drain or a ground-floor tub is where a backup lands first. When that happens, stop using water in the house.
6. A pump alarm. See the alarm section below.
A tank that is three to five years past its last pumping fits the pattern too, since the EPA describes typical pumping as every three to five years and solids only build up. They never leave on their own.
Is a septic tank supposed to be full of water?
Yes, in the sense that it holds liquid by design. The EPA describes the tank as a buried, watertight container whose job is to hold wastewater long enough for solids to settle (sludge) while oil and grease float (scum). So a tank full of water is normal, and looking at the liquid tells you nothing. What counts is the thickness of the sludge and scum layers measured against the outlet. The EPA's test is that the tank needs pumping if the bottom of the scum layer is within six inches of the bottom of the outlet, or the top of the sludge layer is within 12 inches of the outlet. Only someone with the lid open can take that reading.
Will the toilet still flush if the septic tank is full?
It can, for a while, and that is what fools people. Every drain in the house empties into the same tank, and the toilet keeps flushing as long as the water has somewhere to go. Once the tank and the drain field cannot take any more, the EPA says an overloaded drain field floods, sending sewage to the ground surface or causing backups in toilets and sinks. A toilet that gurgles, drains slowly or bubbles when you run the washer is the warning before the backup, not a sign things are fine.
Can I shower or do laundry if my septic tank is full?
Every gallon you use goes into the septic system, because the EPA says all of the water a household sends down its pipes winds up there. If the signs above are showing, use as little water as you can until the tank is pumped. Skip the dishwasher, hold the laundry and shorten showers. If sewage is already coming up in a tub, shower or floor drain, stop using water completely and call.
What fills up a septic tank the most?
The EPA names four things that decide how fast a tank needs pumping: household size, total wastewater generated, the volume of solids in the wastewater and the size of the tank. In day-to-day terms the fast fillers are a garbage disposal (the EPA says frequent use significantly increases the accumulation of sludge and scum), wipes and paper towels, grease, and big laundry days. Our guide to how often to pump a septic tank puts numbers on the schedule.
Is it the tank, the house line or the drain field?
Three different problems look alike from the kitchen.
A full tank
Symptoms spread across the whole house and have been building for weeks. Pumping clears them right away.
A clogged house line
Symptoms usually start with one fixture, or one group of fixtures on the same line, while the septic tank itself is not full. This is a job for a cable and not a truck. Our page on clogged drain repair covers how that goes, and the sewer line backing up page explains the difference between a branch and the main.
A failing drain field
The tank has been pumped and the symptoms come back quickly, or the ground over the field stays wet and smells even though the tank is not full. If a pump-out clears everything for a few days and it all returns, the field is not taking water. That needs its own evaluation, see drain field replacement. Water from roof gutters, sump pumps or other rainwater drainage that ends up over the field is one cause worth checking, because the EPA says excess water slows or stops the wastewater treatment process.
You can sort the three by asking when and where it started. Whole house and slowly points at the tank. One fixture and suddenly points at the house line. Wet ground outside after a recent pumping points at the field.
What does a septic alarm going off mean?
Some systems have a pump tank with a high-water alarm, including pumped and mound systems. Texas A&M AgriLife Extension describes the alarm float as the part that sounds an alarm to warn you when the pump or the system malfunctions, set off when the wastewater in the pump chamber rises above the normal level, and says it should consist of a buzzer and an easily visible light. The EPA says systems with electrical float switches, pumps or other mechanical parts need to be inspected more often, generally once a year. If an alarm sounds, cut back on water and call. Do not just silence it and carry on, because the water keeps arriving whether the pump is working or not.
What can I do while I wait for help?
1. Cut your water use. Hold laundry, skip the dishwasher and shorten showers.
2. Do not pour in a cleaner. The EPA does not recommend septic additives, and nothing poured in makes room in a full tank. Our guide on whether septic additives work has the details.
3. Do not use the toilet as a trash can. The EPA says to flush nothing but human waste and toilet paper.
4. Keep everyone off the area. Children, pets and vehicles stay off the lid and the field.
5. Look, do not open. Walk the yard and look at the ground. Never lift a lid and never lean in. Septic tanks produce hydrogen sulfide and methane. Hydrogen sulfide interferes with the sense of smell at high concentrations, so you cannot rely on your nose, and methane can displace the oxygen in an enclosed space. A cracked or missing lid can also give way underfoot.
What does a septic inspection entail?
In general terms, an inspection answers three questions. How full is the tank? Are the parts inside it sound, meaning the baffles or tees at the inlet and outlet and any effluent filter? And is the liquid leaving the tank reaching a drain field that is taking it? The EPA says a provider will inspect for leaks and examine the scum and sludge layers.
To answer the first, the lid is opened and the depth of sludge and scum is measured. For the second, the inspector looks at the inlet and outlet pipes and the filter, if there is one. For the third, they look at the field and the ground over it for wet areas, odor or surfacing liquid.
Many people have an inspection done before buying a house. A seller's old pumping receipt tells you when the tank was emptied, not what shape it is in.
Our septic pumping page lists what a visit includes:
- Sludge and scum level inspection during every visit
- Baffle and filter checks while the tank is open
When should I stop watching and call?
- Sewage is in a tub, shower or floor drain.
- More than one fixture is slow, or the toilet gurgles when you run another fixture.
- The odor is strong enough to smell indoors.
- The ground over the tank or field is wet, soft or sunken.
- An alarm is sounding.
- You do not know when the tank was last emptied.
Call for septic pumping and ask for the level to be checked, or see the general septic pumping service page. If it turns out the tank is not the cause, the septic overview shows the other parts of the system we work on.
What does it cost to have it pumped?
Septic pumping with American Septic & Sewer is $395 flat for a 1,000-gallon tank, and larger tanks and deep lids cost more. We confirm your tank size and lid depth on-site, in writing, before we start.
Will my toilet flush if the septic tank is full?
It can, for a while, because the toilet keeps flushing as long as the water has somewhere to go. Once the tank and field cannot take more, the EPA says an overloaded drain field floods, sending sewage to the surface or causing backups in toilets and sinks. A gurgling or slow toilet is the warning.
Is it safe to look inside my septic tank?
No. Septic tanks produce hydrogen sulfide and methane, and a damaged lid can give way. Never open the tank or lean over it, and keep children and vehicles off the lids and the drain field.
What should I do if sewage is coming up in the house?
Stop using water, including the washer and dishwasher, and call. More water only pushes more into a tank or line that is already backed up.
Where we work
American Rooter & Drain was established in Caldwell, Idaho in 1945 and has worked the greater Treasure Valley since 1945. American Septic & Sewer provides septic pumping at $395 flat for a 1,000-gallon tank, the size most Treasure Valley homes have, priced by size for other tanks, across Boise, Nampa, Caldwell, Meridian, Kuna, Star and the surrounding Treasure Valley, for homes and rural properties alike. See what we do in Boise, Nampa, Caldwell and Meridian. Call (208) 366-5771, days, nights, weekends and holidays.
