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Quick answer from a licensed plumber: For a septic pump tank, buy a pump the maker rates for effluent. Our pick is the Little Giant 10ECH: a 1/2 HP effluent pump with 3/4 in. solids handling, 45 GPM at 20 feet and a 60-foot shut-off, in a float version (10ECH-CIA-RF) or a manual version for control panels (10ECH-CIM). For a short lift to a gravity distribution box, the Zoeller M98 moves up to 72 GPM but stops at 23 feet of head. On a permitted system, match the flow and head on the design, and ask your health department or a licensed septic installer before you change anything.
Our pick for most septic pump tanks: the Little Giant 10ECH high head effluent pump. On October 6, 2026, Amazon.com did not sell the float version (10ECH-CIA-RF); the manual 10ECH-CIM, for control panels, is linked in its card below.
On a septic system, the pump people mean is the effluent pump. It sits in a pump tank or chamber after the septic tank and sends the settled liquid, called effluent, to the drain field, a mound or a sand filter. It is not a sump pump for ground water and not a sewage pump for raw waste, and the makers rate them differently. This page covers effluent pumps sold by Amazon.com, how to match one to your system, and the floats that run them. For the access lids on the tanks, see septic tank risers.
If you mean pumping out the septic tank itself, that is a service truck, not a pump you buy. The EPA says household tanks are typically pumped every three to five years.
Which Pump Does Your Septic System Use?
| Pump class (Little Giant) | Job | Solids | Where to look |
|---|---|---|---|
| Sump/effluent | Light septic, or pumping to a leach field where gravity feed is not possible | 3/8 to 1/2 in. | This page: Zoeller M98, Liberty 257 |
| Effluent | Septic and grey wastewater; lifts septic wastewater to a leach field | 3/4 in. | This page: Little Giant 10ECH |
| Sewage | Raw sewage, such as a basement bathroom lift station | 2 in. | Best sewage ejector pumps |
| Grinder | Raw sewage ground to a slurry | Grinds solids | Best sewage grinder pumps |
Pump classes and examples from Little Giant’s wastewater pump selection tool, read on October 3, 2026.
Where the pump sits
A gravity septic system has no pump: effluent flows downhill from the tank to the drain field. A pump goes in when the field sits higher than the tank or the design needs pressure. The EPA describes mound systems this way: effluent flows from the septic tank to a pump chamber, where it is pumped to the mound in prescribed doses. Sand filter systems use a pump chamber too, and drip systems need a large dose tank after the septic tank. If the pump lifts raw sewage from the house to the septic tank, that is a sewage or grinder pump, not an effluent pump; see sewage ejector vs sump pump.
Float or control panel?
Look at how the old pump is wired before you order. Some pump tanks use an automatic pump with its own float, or a pump plugged into a piggyback float. Others run a manual (nonautomatic) pump from a control panel with separate floats, and often a high-water alarm. Zoeller’s selection guide sends nonautomatic Model 98 pumps to a piggyback float or a simplex control panel. Liberty says manual pumps built with no plug must use an approved motor control panel, and not to wire a switch in series with the pump cord. If your pump plugs into a panel, buy the manual version, such as the Little Giant 10ECH-CIM.
Sizing: Flow at Your Head
An effluent pump has to deliver enough flow at the height and distance it pumps. Makers publish flow at each height of total dynamic head, which is the lift plus the friction loss in the pipe. The farther toward a pump’s shut-off head you run it, the less it moves. Little Giant lists the 10ECH at 55 GPM at 10 feet and 30 GPM at 30 feet, with a 60-foot shut-off. The Zoeller M98 and Liberty 257 both stop at 23 feet. So a pump tank that lifts 18 feet to a distribution box is near the end of the Zoeller’s and Liberty’s range, and well inside the Little Giant’s (our arithmetic). Plumber’s note: a permitted system often has a design sheet that names the pump or the flow and head it needs. If you have one, match it. If you are replacing a pump that worked, the label on the old one gives you the model, horsepower and voltage to match.
Septic Pumps Compared
| Pump | HP | Solids | Flow at height (maker) | Shut-off head | Float |
|---|---|---|---|---|---|
| Little Giant 10ECH-CIA-RF | 1/2 | 3/4 in. | 55 GPM at 10 ft; 45 at 20 ft; 30 at 30 ft | 60 ft | Piggyback (CIM: none) |
| Zoeller M98 | 1/2 | 1/2 in. | 72 GPM maximum | 23 ft | Integral snap-action |
| Liberty 257 | 1/3 | 1/2 in. | 44 GPM at 5 ft | 23 ft | Vertical magnetic |
From the Little Giant 10ECH spec sheet, Zoeller’s FM2779 data sheet and Liberty’s 250-Series engineering spec. Each linked pump was sold by Amazon.com and in stock on October 3, 2026.
Little Giant 10ECH High Head Effluent Pump
1/2 HP · 115 V, 9 A running · Little Giant lists 60 GPM at 5 ft, 55 at 10 ft, 45 at 20 ft, 30 at 30 ft, 15 at 40 ft · 60 ft shut-off (26 psi) · 3/4 in. solids · 1-1/2 in. FNPT discharge · cast iron body, volute and motor housing · continuous duty · 140 °F max · 10ECH-CIA-RF: piggyback float, 30 ft cord · 10ECH-CIM: manual, for a control panel · 3-year limited warranty
This is the pump to buy for a septic pump tank because Little Giant built it for exactly that job. Its selection tool puts 3/4 in. solids-handling effluent pumps in the column for septic and grey wastewater, with the example “lifts septic wastewater to a leach field,” and the 10ECH page says it is built to handle heavy effluent. It is also the high-head pump on this page: Little Giant lists 45 GPM at 20 feet, 30 GPM at 30 feet and a 60-foot shut-off. That reach matters when the drain field sits uphill or a long way off.
Buy the version that matches how your tank is wired. The 10ECH-CIA-RF has a piggyback float: the pump plugs into the float’s cord. Little Giant’s sheet lists it on at 13 to 16 in. and off at 7 to 10 in.; the Amazon listing gives lower numbers, so check the sheet. The 10ECH-CIM is the manual version with no float, for a tank run by a control panel and separate floats. Little Giant’s manual says the pump is for clean water or effluent with up to 3/4 in. semi-solids, and not for sewage, gravel or sand.
- Little Giant calls it an effluent pump built for heavy effluent
- 60-foot shut-off, the most head on this page
- 3/4 in. solids, per Little Giant
- Piggyback (RF) and manual (CIM) versions
- 115 V only
- Float levels on the Amazon listing differ from Little Giant’s sheet
- Not for raw sewage, per Little Giant
- Three-year warranty
Verdict: The effluent pump to buy for a septic pump tank, in the float or manual version that matches your system.
Not linked: on October 6, 2026, the Little Giant 10ECH-CIA-RF listing on Amazon showed no Amazon.com offer, only other sellers, so we removed its button. We will relink it when Amazon.com stocks it again.
Zoeller M98 Flow-Mate Effluent Pump
1/2 HP · 115 V, 9.4 A (the 230 V D98 draws 4.7 A, per Zoeller) · automatic snap-action float, on at 9-1/2 in., off at 3 in. · 72 GPM max flow · 23 ft max head · 1/2 in. solids · 1-1/2 in. NPT discharge · cast iron, oil-filled · 130 °F max · 9 ft cord on the automatic · 3-year limited warranty
Zoeller titles its data sheet “Model 98 Submersible Effluent/Dewatering Pump,” and its product page says the Model 98 family is designed for high-flow basement sump, dewatering and light effluent applications. It moves a lot of water at a short lift: Zoeller lists a 72 GPM maximum flow. The limit is head. Its maximum is 23 feet, so it suits a pump tank that lifts effluent a short way up to a gravity distribution box, not a mound or a long uphill run.
The linked 98-0001 is the automatic version with its own float. Zoeller’s selection guide says nonautomatic versions run from a piggyback variable level float or a Zoeller simplex control panel, and Zoeller sells the N98 and BN98 that way. The 9-foot cord on the automatic is short for a buried pump tank, so plan where the plug and junction box go. Zoeller lists a 3-year limited warranty.
- Zoeller lists it for effluent and dewatering
- 72 GPM maximum flow, per Zoeller
- Cast iron, oil-filled motor
- Automatic: no separate float to buy
- 23-foot maximum head
- 1/2 in. solids, smaller than the Little Giant’s 3/4 in.
- 9-foot cord on the automatic
- Zoeller calls its effluent duty light
Verdict: The pick for a pump tank that lifts effluent a short way to a gravity distribution box.
Liberty Pumps 257 Sump/Effluent Pump
1/3 HP · 115 V, 5.2 A · vertical magnetic float · 44 GPM at 5 ft · 23 ft shut-off · 1/2 in. solids · 1-1/2 in. discharge · one-piece cast iron housing · quick-connect cord: 10 ft standard, 25 ft on the 257-2 · 140 °F intermittent, 104 °F continuous
Liberty’s installation manual says its 250-series pumps are to be used for handling septic tank effluent and storm water, and its sheet calls the series a sump/effluent pump. The 257 is the version with a vertical magnetic float, which Liberty says can work in a basin as small as 10 in. across for ground water. For effluent, though, Liberty says the basin must be sealed and vented to meet health and plumbing codes, with a minimum of 18 in. across and 24 in. deep.
Liberty’s engineering spec lists a 23-foot shut-off and 44 GPM at 5 feet, so this is a short-lift pump like the Zoeller, with less motor. The quick-connect cord lets you replace the cord without opening the motor, and the 257-2 comes with a 25-foot cord, which helps in a buried tank. Liberty also says to consider a back-up pump and an alarm where losing the pump could cause damage, with the alarm on a separate circuit.
- Liberty lists it for septic tank effluent
- Vertical magnetic float
- Replaceable quick-connect cord; 25 ft on the 257-2
- Lowest amp draw here: 5.2 A
- 1/3 HP and a 23-foot shut-off
- 1/2 in. solids
- Liberty rates continuous duty at 104 °F, intermittent at 140 °F
Verdict: The pick for a small, low-lift effluent basin where a vertical float fits better than a wide-angle one.
Not linked: on October 4, 2026, Amazon.com no longer sold the Liberty 257-2 listing, and the third-party offer on that page carried a different product title, so we removed the Amazon button. We will relink it when Amazon.com stocks it again.
I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.
Floats, Panels and Alarms
On a septic pump tank, the float or control often quits before the pump. Two replacement floats were sold by Amazon.com on October 3, 2026. The Little Giant CFST pump-down control float is for control panels: its listing says it needs a panel, such as a Little Giant or Franklin Electric simplex or duplex panel, and is rated 5 A. The Zoeller 10-0055 Switch-Mate piggyback float is for a pump with no panel: its listing says it converts a nonautomatic 115 V pump of up to 13 A to automatic, with on and off points you set in the field.
Little Giant’s manual says that where a failed pump could cause damage, an automatic back-up system or an alarm should be installed. Liberty says the same and adds that an alarm must be on a separate electrical circuit. The EPA says systems with electrical float switches and pumps should be inspected more often than plain gravity systems, generally once a year, and that a service contract is important for them.
Before You Buy
- Read the old pump’s label. Model, horsepower, voltage and whether it is automatic or manual.
- See what it plugs into. A control panel means a manual pump. A pump plugged into the back of a float’s plug is run by that float; replace it with a pump sold with a piggyback float, such as the 10ECH-CIA-RF, or a manual pump plus a new float. A pump plugged straight into an outlet is an automatic pump with its own float.
- Check the design sheet or permit. If your county has the system design on file, it may list the flow and head.
- Check the solids rating. Effluent pumps here handle 1/2 in. to 3/4 in. solids, not raw sewage.
- Measure the cord run. Little Giant says wiring connections go in a junction box outside the basin, to the National Electrical Code.
Installing It, and When to Call a Licensed Installer
The makers set the basics. Little Giant says to set the pump in a gas-tight basin at least 1.5 feet across and 2 feet deep, vented to local plumbing code, never directly on clay, earth or gravel. It calls for a union above the basin cover, a free-flow check valve that passes 3/4 in. solids, mounted level or at no more than 45 degrees, and a 1/8 in. or 3/16 in. air relief hole in the discharge pipe so the pump does not air lock. Liberty says an effluent basin must be sealed and vented to meet health and plumbing codes, and to check local codes before you buy one. Little Giant says to employ a licensed electrician and to make wiring connections in a junction box outside the basin, to the National Electrical Code; Liberty says to install to the National Electrical Code and local codes.
Liberty also warns not to enter a pump basin after it has been used, because sewage and effluent can give off poisonous gases, and that the gases can be flammable. Plumber’s note: swapping a like-for-like pump in an accessible pump tank is a job some homeowners do, with gloves and the power off. Anything that changes the system, such as a different pump size, new floats or a new panel, belongs to a licensed septic installer and may need a permit. Your local health department can tell you the rules.
FAQ
What is a septic pump?
Usually it means an effluent pump: a submersible pump in a separate pump tank or chamber after the septic tank, which sends the settled liquid to the drain field, mound or sand filter. The EPA describes mound and sand filter systems this way. Pumping out the septic tank itself is a different job, done by a septic service truck.
Can I use a sump pump as a septic pump?
Only if the maker lists it for effluent. Zoeller lists its Model 98 for light effluent and Liberty lists its 250 series for septic tank effluent, but a plain ground water sump pump may not be rated for it. Little Giant’s selection tool puts 3/4 in. solids effluent pumps in the septic column.
What size septic pump do I need?
Match the flow at the head your system needs. If your system has a permit or design sheet, it may list the pump or the flow and head; replace like with like. Then check the maker’s table: Little Giant lists 45 GPM at 20 feet for the 10ECH, while the Zoeller M98 and Liberty 257 top out at 23 feet of head.
Do I need a professional to replace a septic pump?
For a permitted system, check with your local health department or a licensed septic installer first; many systems have rules about the pump, floats and alarm. Liberty and Little Giant both say to follow the electrical and local codes, and Little Giant says to employ a licensed electrician. Never climb into a pump tank: Liberty warns that effluent can give off poisonous gases.
How often should a septic tank be pumped?
The EPA says household septic tanks are typically pumped every three to five years and inspected at least every three years. It says systems with pumps, float switches or other mechanical parts should be inspected more often, generally once a year.
Why Trust Plumbing Picks
Plumbing Picks is written by a licensed Georgia journeyman plumber. Every spec here comes from the maker documents linked below, or from the Amazon listings we link; nothing comes from hands-on testing. On October 3, 2026, every linked listing was sold by Amazon.com and in stock. If you buy through a link we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.
Sources
- Little Giant: 10ECH Series effluent pump, spec sheet 996251, 9EC/9ECH/10ECH owner’s manual
- Little Giant: wastewater pump selection tool (M5244)
- Zoeller: Model 98 pump page, technical data sheet FM2779, pumps and systems catalog FM0532
- Liberty Pumps: 250-Series sump/effluent pump sheet, engineering specification, installation manual 7035000
- U.S. EPA: Types of Septic Systems, How to Care for Your Septic System
- Amazon listings for the Little Giant 10ECH-CIA-RF and 10ECH-CIM, Zoeller M98, Liberty 257 and 257-2, Little Giant CFST float and Zoeller 10-0055 Switch-Mate (linked above)
Bottom Line
A septic pump is an effluent pump in a pump tank after the septic tank. The Little Giant 10ECH is the one to buy for most systems, because Little Giant rates it for septic effluent with 3/4 in. solids and it reaches 60 feet of head. The Zoeller M98 and Liberty 257 suit short, low lifts. Match the float or panel you have, match the flow and head your system needs, and leave changes to a permitted system to a licensed septic installer.