Septic pumps

Does your system have a pump?

A pump is needed when wastewater has to go uphill or be delivered in measured doses under pressure.

A pumped system should also have a high-water alarm. Arkansas, Oklahoma and Tennessee rules require one (see the alarm section below).

• The drain field sits higher than the septic tank.
• The house plumbing sits lower than the tank, so sewage has to be lifted (a lift station).
• The field is a low-pressure, drip, spray, mound or sand filter design that needs measured doses.
• The design doses a gravity field to spread effluent more evenly.

Sources: Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 8: Gravity Distribution Methods and Soil Dispersal Trenches (no date shown); Oklahoma DEQ, OAC 252:641 Individual and Small Public On-Site Sewage Treatment Systems (PDF, amendments effective through Sep 15, 2024); Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08); US EPA, Types of Septic Systems (last updated May 4, 2026)

Types of septic pumps

Low-head pumps move larger volumes at low pressure, for pumped gravity fields and low-pressure dosing. High-head pumps move less water at higher pressure, for drip and spray systems. The pump has to fit the design.

Sources: Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08); Arkansas State Board of Health, Rules Pertaining to Onsite Wastewater Systems (effective Sep 5, 2024); US EPA, Wastewater Technology Fact Sheet: Sewers, Pressure (EPA 832-F-02-006, September 2002)

The pump tank

The pump sits in its own tank or in a separate compartment of the septic tank. The tank has to hold one dose, keep a minimum level for the pump, and leave reserve space above the alarm so there is time to get a repair.

Texas A&M says many home pump tanks hold 500 gallons, and a 1,000 gallon tank gives about two days of storage after the alarm goes off.

State rules set minimums. Oklahoma requires a lift station tank of at least 1,000 gallons, with controls set so it is never more than half full. Missouri requires emergency storage equal to one day's design flow. Arkansas requires emergency storage above the alarm of at least one third of estimated daily use.

Good pump tanks have a riser to the surface, a secured lid, and a union on the discharge pipe plus a lifting rope, so the pump can be pulled without anyone entering the tank.

Sources: Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08); Oklahoma DEQ, OAC 252:641 Individual and Small Public On-Site Sewage Treatment Systems (PDF, amendments effective through Sep 15, 2024); Arkansas State Board of Health, Rules Pertaining to Onsite Wastewater Systems (effective Sep 5, 2024)

Floats and controls

Float switches hang from a pipe called a float tree. An on/off float starts the pump when the tank reaches the dosing level and stops it at the minimum level. A separate high-water float sets off the alarm. Some systems add a backup off float.

Some systems run on demand, whenever the tank fills. Others use a timer to dose on a schedule, which spreads the day's flow out evenly.

Floats can tangle or fail. A float rated for less electrical current than the pump draws will burn out.

Sources: Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08); Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Troubleshooting System Problems (no date shown)

The high-water alarm

Every pumped system should have an alarm with a buzzer and a light, on a separate circuit from the pump. It warns you before the tank overflows or backs up.

If it sounds, check the breaker, stop using water (no laundry or dishwasher), and call your service provider. Only the reserve space is left. Texas A&M's example: a pump tank for a three-bedroom house may hold just 80 more gallons after the alarm. See the septic alarm guide.

Sources: Arkansas State Board of Health, Rules Pertaining to Onsite Wastewater Systems (effective Sep 5, 2024); Oklahoma DEQ, OAC 252:641 Individual and Small Public On-Site Sewage Treatment Systems (PDF, amendments effective through Sep 15, 2024); Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Tennessee Rule 0400-48-01, Regulations to Govern Subsurface Sewage Disposal Systems (April 2014, revised; current file on the TN Secretary of State site); Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08)

Pump maintenance

Pumped systems need more attention than gravity systems.

• Have the pump, floats and alarm checked every year.
• Test the alarm with its test button if the panel has one.
• Clean the effluent screen or pump vault filter when the tanks are pumped; Missouri says pressure line filters every six months.
• Have the pump tank pumped when the septic tank is pumped.
• Have wiring and conduit checked for corrosion; sewer gas corrodes connections that are not sealed.
• After a long power outage, ask your provider about limiting the first doses so the backlog does not flood the field.

Sources: Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08)

How long septic pumps last

The EPA says many pumps and controls need replacing every 10 to 20 years. For grinder and effluent pumps on pressure sewers, the EPA's 2002 fact sheet gives 4 to 10 years between service calls as a reasonable estimate for quality installations.

Warning signs include the alarm, unusual noise or vibration, and backups. Fixr lists too much or too little noise, leaking, a faulty float or a burnt-out motor as common signs of a bad pump.

Sources: US EPA, Frequent Questions on Septic Systems (last updated Mar 11, 2026); US EPA, Wastewater Technology Fact Sheet: Sewers, Pressure (EPA 832-F-02-006, September 2002); Missouri DHSS, An Onsite Wastewater Treatment System Owner's Manual, Chapter 6: Pumps and Pump Tanks (no date shown); Fixr, Septic Tank Repair Cost (Adam Graham, updated January 31, 2025)

Replacing a septic pump

A new pump must deliver the same flow at the same pressure the system was designed for. Too little and the field doses unevenly; too much can damage the system. Oklahoma requires pumps built for sewage or liquid with fine solids and rated for the daily flow, distance and lift. Tennessee requires a good quality effluent pump sized to the flow and head.

[EST] Replacement cost varies widely between guides:

Budget for new floats too if they are worn. Grinder pump prices were not found in a source that could be read (see unverified).

• [EST] HomeAdvisor installation page (updated Jun 20, 2026): pump replacement $800 to $1,400.
• [EST] HomeAdvisor repair page (updated Jun 19, 2026): repair $250 to $400; replacement $1,000 or more.
• [EST] Fixr repair page (updated January 31, 2025): replacement $250 to $500 (its table says labor included); repair $250 to $1,500.
• [EST] Fixr installation page (updated January 31, 2025): $200 to $500 if the tank pump fails.
• [EST] Float replacement: $150 to $500 (Fixr).

Sources: Texas A&M AgriLife Extension, L-5346 Pump tank (Lesikar and Persyn, 9-08); Oklahoma DEQ, OAC 252:641 Individual and Small Public On-Site Sewage Treatment Systems (PDF, amendments effective through Sep 15, 2024); Tennessee Rule 0400-48-01, Regulations to Govern Subsurface Sewage Disposal Systems (April 2014, revised; current file on the TN Secretary of State site); HomeAdvisor, Septic System Installation Cost (updated Jun 20, 2026); HomeAdvisor, How Much Does Septic Tank Repair Cost in 2026? (updated Jun 19, 2026); Fixr, Septic Tank Repair Cost (Adam Graham, updated January 31, 2025); Fixr, Septic System Installation Cost (updated January 31, 2025)