Macerator breakdown hums, doesn't pump out or keeps switching on
Is the water standing in the bowl and is the macerator only humming? Turn off the power and call 070 783 0224 or send a video via WhatsApp.
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A macerator (toilet grinder) pumps away wastewater from a toilet, shower or washbasin where a normal drain is not possible, for example in a loft, basement or extension. When something goes wrong, you notice it immediately: the water remains standing, the motor hums or the unit switches on every few minutes. One customer described it exactly like this: "the motor hums, but the water is not being pumped away". Below is what is usually going on.
Short answer
If the motor hums but doesn't pump, there's usually something stuck in the blades or the pump (a cloth, hair, cotton buds), or the discharge pipe is blocked or scaled up. If it keeps switching on briefly, water is often leaking back via a non-return valve or a tap or cistern is running somewhere. When in doubt, switch off the power first: opening a macerator while it's live is dangerous.
- Only toilet paper and faeces in it; no wipes, tampons or kitchen roll.
- Switch off the power before you try anything.
- Recurring problem: often limescale in the pressure pipe or a worn non-return valve.
Call me back
Leave your name and number and we'll call you. Prefer immediate contact? Call 070 783 0224 or message us.
What's usually the problem
- Motor hums, water remains standing. The blades or impeller are stuck due to something that does not belong there. Wet wipes are number one, even if the packaging says "flushable".
- Pumps away slowly, water runs back. The pressure pipe is blocked or narrowed by limescale and grease, or the non-return valve no longer closes. The water that has been pumped up then runs back into the macerator.
- Switches on briefly every few minutes. Water is entering without anyone doing anything: a continuously filling cistern, a dripping tap on a connected washbasin, or water flowing back through a leaking valve.
- Does nothing at all. Power off (RCD tripped, plug disconnected) or the pressure switch and membrane are faulty.
- Smells or leaks. Poor ventilation or a loose hose. In case of a leak, always switch off the power first.
What you can safely do yourself
- Stop flushing. Every extra bit of water makes it worse if the system is not pumping away.
- Pull out the plug or switch off the circuit. Only then look. A macerator has sharp blades.
- Check whether a tap or cistern is running. If the unit keeps running, check the toilet and washbasin connected to it.
- Switch the power back on and flush once. Sometimes it was a temporary blockage. If it hums again without pumping out, leave it and call.
Do not use drain unblockers or caustic descalers in a macerator. They can damage the rubber parts and the membrane, and they make the work more dangerous for the technician. There are special descalers for macerators; only use what the manufacturer of your unit recommends.
How we tackle a macerator breakdown
- Video or description in advance. The sound tells us a lot: humming, rattling or nothing. Make and model help us bring the right parts.
- Isolate from power, open and clean. We remove what is blocking the blades and the impeller and check whether the blade still turns freely.
- Check the pressure pipe and non-return valve. If the pipe is scaled or blocked, we'll clean it. We'll replace a worn valve.
- Testing with all connected fixtures. Toilet, shower, washbasin: everything must pump away properly without the unit continuing to run afterwards.
If the unit has failed and parts are no longer available, we'll discuss replacement. Sometimes it's also an opportunity to see whether a normal gravity drain is still possible, for example during a renovation.
What does repairing a macerator cost?
A macerator breakdown is not listed as a fixed job in our price list, because the work varies greatly. You will receive the price in advance, after a video or photos.
| Item | Excl. VAT | Incl. 21% VAT |
|---|---|---|
| Call-out charge: first 30 minutes + diagnosis | € 100 – € 165 | € 121 – € 199,65 |
| Toilet blockage | € 165 | € 199,65 |
| Install drain | € 75 | € 90,75 |
If a job is not listed in the price list, you will receive a tailored quote after photos or a short visit. For that visit, the call-out charge is € 100 – € 165 excl. VAT (€ 121 – € 199.65 incl.) for the first half hour including diagnosis, plus travel costs of € 35 excl. VAT (€ 42.35 incl.). You will always hear the price before we start.
Questions about a macerator or toilet macerator
Why does my macerator hum but not pump?
Usually something is stuck in the blades or the impeller, such as a wet wipe, hair or cotton buds. A blocked or scaled-up pressure pipe can also be the cause. Switch off the power and do not open the unit while it is live.
Why does my macerator keep running, even when no one is flushing?
Water is then entering: a continuously filling cistern, a dripping tap on a connected basin, or water flowing back through a faulty non-return valve. First check whether the toilet is running.
What should not go through a macerator?
Only faeces, urine and toilet paper. No wet wipes, kitchen roll, tampons, sanitary towels, cotton buds, hair or grease. Even wipes labelled "flushable" can block the unit.
Can I pour drain cleaner into a waste disposal unit?
Better not. Caustic products can damage rubber parts and the membrane. Only use a descaler recommended by your appliance manufacturer.
What does macerator repair cost?
That depends on the cause. We work with a starting rate of €100 – €165 excl. VAT (€121 – €199.65 incl.) for the first half hour including diagnosis, plus call-out charges. After a video or photos you will receive a price in advance.
Can you replace a macerator with a normal drain?
Sometimes. That depends on the height and the distance to the riser. During a renovation, it is worth having that checked.
