Septic Tank Pumps

Where a septic tank pump fits in

Most septic tanks and small sewage treatment plants drain by gravity. A pump is needed when the drainage field or sewer connection sits higher than the tank outlet, or too far away for a gravity fall. The pump sits in a chamber after the tank, collects the settled effluent and lifts it on in batches. Sludge and scum stay in the tank and are removed by a registered waste carrier at regular intervals.

In England, septic tanks and small sewage treatment plants must meet the general binding rules or hold an environmental permit, and those rules control where the effluent can go. GOV.UK explains the permits you need for septic tanks. Check your discharge point is compliant before investing in a new pump.

How to choose a pump for effluent

Four points decide the right pump:

• Solids handling: a vortex impeller recessed above the flow passes soft solids. The JS-250SV handles soft solids up to 36mm and the Pentair Biox up to 40mm.
• Head and flow: add the vertical lift from the chamber to the discharge point to an allowance for pipe friction. The JS-250SV is rated at 240 litres per minute with a maximum head of 6.5m, so suits short lifts. The Biox 400/12 reaches 12m.
• Automatic control: a float switch starts and stops the pump with the level. The automatic JS-250SV comes with M/3 or Agma float options.
• Voltage: most rural properties run 230v single phase pumps. The JS-250SV is also made in 110v for site use.

Septic tank pumps we stock

Our effluent pumps include the JS-250SV and JS150SV sewage vortex pumps, the JS SV single phase range, the Pentair Biox with its stainless steel body and impeller, the Pentair Jung Nocchi Priox and the Dreno Compatta.

Alarms, floats and installation

Fit a high level alarm in every effluent pump chamber. If the pump fails without one, the first sign is often effluent backing up into the tank or the drains. Our controls range covers alarms and panels, and the float switch guide explains switching levels.

Use a non-return valve on the rising main, and consider a coupling foot so the pump lifts out on a chain. The JS-250SV is compatible with the SR50 coupling foot and claw. Never climb into a sewage chamber: the gases in an enclosed chamber can kill.

Related applications

If the whole building sits below its outfall, a package pumping station may be simpler. For the full range, see sewage pumps.

Frequently asked questions

Can I pump out my own septic tank?

No. The sludge and scum in a septic tank must be removed by a registered waste carrier with a tanker, who disposes of it legally. A septic tank pump only handles the settled effluent that leaves the tank, lifting it to a drainage field, soakaway or higher sewer.

What size pump do I need for a septic tank outlet?

Work out the vertical lift from the pump chamber to the discharge point and the length of the rising main, then pick a pump that still gives useful flow at that head. For a short lift to a nearby drainage field, a light duty vortex pump such as the JS-250SV is often enough.

Should I use a vortex or a grinder pump for effluent?

For septic tank and treatment plant effluent, a vortex pump is the usual choice because it passes soft solids through an open passage with less to wear or block. Grinder pumps chop solids so they can travel through small bore pressure pipes over long distances or great heights.

How will I know if my septic tank pump has failed?

Without an alarm, you may not know until effluent backs up into the tank or drains. A high level alarm sounds or lights when the chamber fills above its normal level, giving you time to call for help before it overflows. Fit one to every effluent pump chamber.