A self-priming Wassermann pump, 4GPM sized for everyday van use at £64.61

A 12V diaphragm pump uses a small DC motor to flex a rubber diaphragm back and forth, drawing water in on one stroke and pushing it out under pressure on the next. A built-in pressure switch senses when line pressure drops (a tap opening) and switches the motor on automatically, then cuts it off once pressure is restored — that's why it self-primes and starts on demand rather than running continuously.

This pump is rated at 4GPM (about 15.1 litres a minute) and up to 45 PSI, enough for a van shower head or kitchen tap without a noticeable drop when a second outlet is open.

Most 12V diaphragm pumps in this flow and pressure range draw somewhere between 3A and 8A while running. Check the rating plate on the pump itself for the exact figure and fuse the circuit above it — never guess and under-fuse a water pump circuit.

The most likely cause is an air lock or a dry tank. Check the tank actually has water in it, then check every fitting on the suction side (between the tank and the pump) for a loose connection or split hose — a pump can run perfectly and still fail to prime if it's drawing in air instead of water. A blocked inlet strainer is the next thing to check.

A pump that clicks on for a second or two even with every tap closed almost always means a small leak somewhere downstream is letting pressure bleed off, re-triggering the pressure switch. If the pump has an accumulator tank, a lost air charge in the tank causes the same symptom — check every joint for weeping before assuming the pump itself has failed.

No. It self-primes, meaning it draws water up from the tank on start-up rather than needing the line filled by hand first.

Yes, it's a diaphragm-type pump, which is the standard design for 12V fresh water delivery in campervans and caravans.

Most diaphragm pumps, including this one, have a check valve built into the pump head that stops water flowing backward when it's switched off, so a separate in-line valve usually isn't needed — confirm against the manual for this exact model if you're plumbing in a long or unusual pipe run.

Running any diaphragm pump dry for an extended period can wear the diaphragm prematurely, so it's worth fitting a low-level cut-out or simply keeping an eye on tank level, particularly if the model doesn't list dry-run protection.

Most 12V diaphragm pumps of this type can be plumbed with an inline accumulator tank to reduce cycling, though it isn't included with this listing.

With normal touring use and occasional descaling in hard-water areas, a quality 12V diaphragm pump typically runs for several years before it needs attention. The diaphragm itself is the part most likely to wear out eventually — most manufacturers, including this one, sell replacement diaphragm and valve kits separately rather than requiring a full pump swap.

GPM (US gallons per minute) and LPM (litres per minute) both measure flow rate. This pump's 4 GPM rating works out to about 15.1 LPM, so you can compare it directly against pumps listed in either unit.

It runs on a standard 12V DC supply from a leisure battery, typically through an inline fuse and a manual or pressure-activated switch — follow the wiring guidance in the box rather than connecting directly to an unfused feed.

It uses standard push-fit or threaded connectors common to caravan and campervan plumbing; check the port size in the specification table against your existing hose or pipe before ordering.

Diaphragm pumps of this type produce an audible motor and valve click during operation; mounting it on rubber isolation feet away from a thin panel wall reduces the vibration passing into the cabin.

Yes, we deliver across the UK. Your exact delivery charge and estimate are calculated at checkout from your address, shown before you pay.

Yes, in line with our returns policy — please keep the original packaging, since a pump is easier to return safely in its original box.

A specific warranty length isn't confirmed in our product record, so we won't state a figure we can't stand behind. Your statutory rights apply regardless, and you're welcome to ask us before ordering.