Pond pump repair sounds pretty intimidating. After all a good pond pump is a pretty complicated piece of kit, all wires, cogs, circuitry and complications. Surely you must need a degree in nuclear physics and some sort of Dr Who sonic screwdriver to even get it out of the case?

Well no, actually, pond pump repair is actually pretty simple for the most part. Usually your pump will have stopped working because of something simple - a pesky twig, a pile of gunk and leaves or a build-up of blanket weed. And generally these things can be prevented with simple pond pump maintenance. A bit of cleaning and care is better than pond pump repair any day.

So your pond pump is running fine and one day you find yourself wondering, why has my pond pump stopped working?

Before you dive into your pond, rip out the pump, package it up and send it back to where you bought it, you can save yourself the bother by some simple procedures.

Pond pump repair need not be left to the experts every time. These things are not as tricky as you might think. Remember, prevention is better than cure. That's our polite way of saying, clean the thing once in a while and you'll prevent common problems with your pond pump. Basic pond pump repair isn't as tricky as it sounds, but often it's just a case of light servicing.

Here at Swell we send out hundreds of pond pumps every week, and every week, we receive a dozen pumps sent back from customers who think their pump isn't working. And in 10 of every 12, the pump is fine and the whole issue could have been resolved with some simple maintenance.

Pond pump repair: Easier than you think

Swell returns manager Phil Cross tests and services any pond pumps that are sent back and for the most part, he can repair any issues in two minutes with a screwdriver and some paper towels. Pond pump repair often isn't actual repair - more like "pond pump spot maintenance." 

Phil explained: "Pond pump repair really isn't that complicated. When a pump stops working it's usually because of one of two things. Either the owner has a problem with their electric, or they haven't bothered to do any basic maintenance on their pump."

The power source can be an issue that is easily resolved as well. Because pond pumps are designed to be used outdoors they don't come with a three pin fused plug on like white goods.

Because they live in an extreme environment (for electric, you can't get much more extreme than under water) they are very cautious about electricity. Therefore you should always invest in a Residual Circuit Detector (RCDD).

Phil recommends the Blagdon Powersafe Water Garden Circuit Breaker. As far as your pump is concerned this is the best tenner you'll ever spend. As soon as there's an electrical problem it trips. That should generally tell you the problem is at your end (your home's electricity) - so just plug a kettle in to test it. If the kettle doesn't work, the problem is with your electrics, if the kettle works fine, the problem is at the pump end.

Phil said: "A common problem in pond pump repair and diagnosis is with the cable. People bury them underground and then cut through them with a spade. Your wiring must always be protected. And if you have multiple appliances you should use a switchbox, like the Blagdon Powersafe Four Outlet Switchbox."

Circuit detectors and switchboxes are a must for outdoor kit like pond pumps.

So you haven't got a problem with your electrics or wiring and your pond pump isn't working, or maybe it's working sporadically. This is where maintenance comes into play. Phil said: "It doesn't matter how good a pond pump is, they will always let in particles from your pond, and over time these particles act like sandpaper and become an abrasive on your rotor. Some basic spot cleaning resolves this issue easily."

Pond pump repair: A simple guide

So how do you go about pond pump repair and maintenance? Phil let us into his workshop and explained. "You start at one end and work your way to the pump," he said. "Start by checking the power supply, then the cable, then the pump." As Phil took us through the stages of diagnostics he showed us one pump that had been sent back by a customer, an Oase Eco Max 4000 - a top of the range pump. But even a top of the range pump needs a little TLC.

"Straight away I can see they have a problem with blanket weed," said Phil. And sure enough the pump's outer casing is now a striking shade of green. It stands to reason - blanket weed in the pond, equals blanket weed in the pump. Something that doesn't make for happy running.

With a few turns of the screwdriver Phil had the pump open. Nothing fancy, just four screws and we're into the pump. He had of course ensured that the pump was not plugged in.

Now you can easily check for any simple blockages. This pump is pretty clean, so maybe the problem is inside.

Check both ends to check for any twigs and grit. Again, this one looks clear, so we need to check out the rotor and impeller.

"First you have to check if there's any blockages in the impeller. Pumps suck in anything that's in your pond. So if you have overhanging leaves, berries and twigs, these can end up blocking the impeller - but this one is fine."

So if the impeller is fine what's the next stage. Phil removes the rotor and sure enough it has been marinated in a cocktail of blanketweed, slime and grit. Phil takes a few paper towels, wipes the rotor and it comes up as good as new. Be sure to check the impeller shaft is free from debris too.

If your pond filter contains a pre-filter, such as a sponge, make sure you keep it clean. We've previously had pond pumps returned which were so badly clogged with mud that they had caused the motor to burn out. When that's caused by lack of maintenance, it's not covered by the warranty.

Similarly, if you buy a combined pond pump, filter and UV, do make sure you check inside to see if there are any plastic bags still on the media. Some suppliers place biological filter media in plastic bags and it's vital you remove these, otherwise they can block the flow of water and cause the pump to break.

But pond slime isn't the only issue. Phil said: "The rotor is particular prone to blockages in the south of England. They have quite hard water that is chalky and causes limescale on the rotor. It becomes like a cement and makes it difficult for the rotor to do its job."

Limescale can be removed by soaking in white vinegar.

Phil puts the pump back together, drops it into his testing pond, and the pump now works fine. And the whole process could have been prevented with some simple maintenance.

"Another thing you should remember," he said, "is to always test your pump in water. Many of them will not run dry. And with some pumps like Oase they also have a sensor that stops them working if another device in the pond has an electrical problem."

Phil concludes that prevention is better than cure in pond pump repair.

He said: "Ten out of every 12 pumps we have sent back have stopped working because they haven't been maintained or something as simple as a twig. And why is there this debris? Usually because they haven't looked after their filter either. How often have they changed their sponges?"

And Phil reiterates that it doesn't matter how good a pump is, if you don't maintain it expect problems.

He said: "Oase have always been the Rolls Royce of pond pumps, then you have your Blagdon, Hoselock, Fishmate and now Bermuda. They all get sent back to us because they all require maintenance. Just clean it at the start of the season in Spring and clean it again in the Autumn and you've saved yourself a lot of headaches."

Pond pump repair is often a case of "a stitch in time saves nine."