The names are similar enough that they get mixed up all the time, but a sewage pump and a sump pump are built for different jobs. Buy the wrong one and you either pay for solids handling you do not need, or, worse, fit a pump that will block. The difference comes down to one thing: what the pump has to move.
The clean way to remember it: a sewage pump is almost always a sump pump, but a sump pump is not necessarily a sewage pump. A sump pump is defined by what it does, sitting in a sump and emptying it. A sewage pump is defined by what it handles, foul water with solids. Because a sewage pump also sits in a chamber and pumps it out, it is a sump pump too. But most sump pumps are built for clean water, so they cannot handle sewage.
What a sump pump does
A sump pump removes relatively clean water that has collected in a sump: a pit or chamber that gathers groundwater, surface water or drainage. Think of a flooded cellar, a basement waterproofing system, a high water table, or rainwater pooling in a chamber. The water is broadly clean or only lightly dirty, carrying small particles at most. Sump pumps are designed to switch on as the water rises and off as it falls, keeping a space dry. Our guide to what a sump pump is and how to install one covers this in full.
What a sewage pump does
A sewage pump handles foul wastewater that contains solids: the discharge from toilets, soil pipes and similar. It is built to pass or break down solids that would instantly clog a sump pump, and it is usually installed in a sealed chamber or tank below the drainage level, often where waste cannot flow to the sewer by gravity. Because it handles foul water, a sewage installation also has to meet building regulations, which we cover in our guide to sewage pump building regulations and our ultimate guide to sewage pumps.
The real difference: solids handling
The dividing line is the impeller and the size of solid it can pass. A sump pump has tight internal clearances suited to clean water, so it handles only small particles. A sewage pump is built the opposite way: a vortex impeller lets soft solids pass through almost without touching the impeller, while a cutter pump chops solids up before pumping them. The APP SV is a good example of a solids-handling sewage pump. That solids capability is exactly why a sewage pump cannot also pump a floor down to the last millimetre: the large clearances that pass solids cannot pump low or build high pressure. It is a physical trade-off, not a quality difference.
Which one do you need?
If you are clearing clean groundwater, surface water or a flooded space, you want a sump pump, drainage pump or puddle pump. If you are pumping foul water with solids, such as a basement toilet or a property below the sewer line, you need a sewage pump, usually as part of a chamber or packaged pump station. If in doubt, tell us what the pump will be moving and where, and we will steer you to the right collection.
Browse sump pumps or sewage pumps, or call the team on 0115 987 0358.
Frequently asked questions
What is the difference between a sewage pump and a sump pump?
A sump pump removes relatively clean water collected in a sump, such as groundwater or flood water, and handles only small particles. A sewage pump handles foul wastewater containing solids, using a vortex or cutter impeller. The key difference is solids handling.
Can I use a normal sump pump for sewage?
No. A sump pump's tight clearances are made for clean water and will block on the solids in foul water. Sewage needs a purpose-built sewage or cutter pump that can pass or break down solids.
