RV water pump problems: no pressure, constant cycling, and what each fix costs

RV water systems fail in a small number of predictable ways, and the useful first step is figuring out which side of the system has the problem. That takes about ten minutes and it is the difference between a $250–$500 pump replacement and a fitting you can tighten by hand.

Check this first (ten minutes)

Is there water in the fresh tank? Tank sensors lie constantly, particularly after a summer in storage. Do not trust the panel.
Compare city water to pump. Hook up to the city inlet and open a tap. Good pressure on city and nothing on the pump narrows the fault to the tank, the strainer, the pump, or its check valve. The reverse narrows it to the city inlet side.
Look at the pump’s inlet strainer. Clear plastic housing, usually right at the pump. Debris, scale, or a collapsed screen in there will starve the pump. This is the single most common fix.
Listen to the pump. Running smoothly but no water means it is not picking up: air leak on the suction side, clogged strainer, or a dry tank. Running rough or loud usually means air or a failing pump.
Open a tap and let it run. A pump that eventually catches and delivers was airlocked. This is normal after filling an empty tank and it is not a fault.
Walk the rig with a torch. Look under the sink cabinets, at the water heater connections, behind the toilet, and at the low point drains. A leak that is escaping to the outside will show as damp underbelly or a drip line on the ground.

What is usually wrong

What you observe	Likely cause	Fix and cost
Pump runs, no water at all	Empty tank, clogged strainer, or a suction air leak	Often under $250
Pump cycles rapidly with taps closed	Small leak, failed check valve, or toilet valve seeping	$150–$400
Weak pressure everywhere	Failing pump, partly closed valve, or a blocked filter	Pump $250–$500
Weak pressure at one fixture only	Aerator or that fixture’s cartridge	Usually under $200
Pump will not run at all	Fuse, switch, wiring, or a dead pump	$150–$500
Water in the underbelly or a drip on the ground	Line or fitting failure	Plumbing repair $200–$800
Fine when on city water, nothing on the pump	Pump side	Pump or strainer
Fine on the pump, nothing on city water	City inlet, check valve, or regulator	Usually under $250

Ranges come from the pricing page, plus the $75–$150 trip fee and $125–$190 hourly labour.

The Arizona angle

Heat and plastic. A rig stored through a Phoenix summer sees interior cabinet temperatures well above what any plumbing fitting enjoys. PEX fittings, quick-connects, and pump mounting grommets all age faster here, and the classic October call is a rig that was fine in April and now has a fitting weeping behind the shower wall.

Hard water and scale. East Valley water is hard. Scale collects in strainers, in the water heater, in fixture aerators, and in the pump’s own check valve. An inline filter and an annual strainer clean solve most of it.

Dry storage does damage. Systems left empty and hot dry out seals. Pumps that sat dry for five months sometimes need to be run a few minutes before they seal up, and sometimes never do.

Pressure at the pedestal. Some East Valley resorts deliver higher city pressure than an RV system is designed for. A regulator at the inlet is cheap insurance and prevents the kind of blowout that empties a fresh tank into a cabinet while you are at dinner.

When you cannot find the leak

Water tracks. A leak at a fitting behind the water heater can show up on the floor eight feet away, and a leak inside the underbelly may not show at all until the coroplast bellies down. If the pump cycles and nothing is visible, a pressure test is a faster and cheaper answer than pulling panels one at a time, and that is part of what the diagnosis visit is for.

What to expect on the call

Tell us whether city water works, whether the pump runs, what the strainer looks like, and whether you have seen any water where it should not be. Most pump calls can be narrowed on the phone to two possibilities. Pump repairs are done on site across Mesa, Apache Junction, Gilbert, Tempe, Chandler, and Queen Creek.

Frequently Asked Questions

My RV water pump runs constantly and never builds pressure. Why?

The pump cannot reach its cutoff pressure, which means either it is not moving water, or water is escaping somewhere. Air in the line, a strainer clogged with debris, a failed check valve, a tank that is empty, or a leak you have not found yet are the usual five.

What does an RV water pump replacement cost?

$250–$500 including the pump, fittings, and labour. Strainer cleanings, check valves, and loose fittings are much cheaper, often just the trip fee plus part of an hour, which is why the diagnosis comes first.

The pump cycles on and off every few seconds even with the taps closed. Is that bad?

It means pressure is bleeding off somewhere: a small leak, a failed check valve, a toilet valve seeping, or a water heater bypass valve partly open. It is also hard on the pump. Worth finding, and usually cheap when you do.

I have city water pressure but nothing from the pump, or the reverse. What does that mean?

It tells you a lot. Good city pressure and nothing on the pump means the problem is on the pump side: tank, strainer, pump, or its check valve. Good pump pressure and nothing on city water means the city inlet, its check valve, or the regulator.