Mobile RV Water Pump Replacement Across Florida
A 12V demand pump that cycles constantly, loses prime, or delivers no water is the most common plumbing call in mobile RV service. We carry the most common Shurflo and Flojet pumps for same-call replacement.
The demand pump in a typical RV draws roughly 6-8 amps at 12V and is designed to cycle only long enough to restore a set pressure - usually between 35 and 55 PSI depending on the regulator. When it runs without stopping, the problem is almost never the pump itself but rather a failed pressure switch, a weeping check valve, or an open fitting downstream that lets pressure bleed away the moment the pump stops.
Why a Running Pump Delivers No Water
A pump that hums or clicks but moves no water has usually lost its prime. In Florida's heat, flexible tubing between the tank outlet and the pump can develop micro-cracks that admit air without leaking water, and air in the suction line breaks prime completely. The pump spins against nothing and produces no flow even at full speed.
Before condemning the pump, Jesse always checks the inlet strainer, which sits between the tank and the pump body. A strainer clogged with tank sediment or biofilm restricts flow enough that the pump appears dead. Cleaning or replacing the strainer takes ten minutes and has saved dozens of pumps from unnecessary replacement.
Constant Cycling - What It Means and What Causes It
A demand pump cycles because it is doing exactly what it was designed to do: restore pressure the moment pressure drops. If the pressure drops continuously - due to a weeping fixture, a pin-hole in a PEX joint, or a check valve that won't seat - the pump runs every few minutes even with nothing open. This is not a pump failure; it is the pump reporting a system failure.
The other cause is a weak or miscalibrated pressure switch. Switches are adjusted with a small screw on the pump body, and Florida heat ages the diaphragm inside them. A switch that triggers at 20 PSI instead of 35 PSI will cycle the pump far more frequently than necessary and can accelerate wear on the motor. Switch replacement is a minor service, usually accomplished without draining the lines.
How Long an RV Water Pump Should Last in Florida
A quality Shurflo or Flojet pump installed correctly should run 50,000 to 80,000 cycles before any wear-related failure. At typical usage that is five to ten years, but Florida adds variables that compress that lifespan. UV degradation of inlet tubing, mineral deposits from well-fed campgrounds, and the corrosive air near the coast all attack pump internals faster than in dry climates.
The single best practice that extends pump life in this state is an accumulator tank - a small pressure vessel that stores a half-gallon of water under pressure so the pump does not cycle every time someone opens a faucet briefly. Pumps installed with accumulators on Florida coaches consistently outlast those without them by several years.
Running Dry - The Real Failure Risk
An RV demand pump has no automatic dry-run protection. If the fresh tank runs empty and the pump continues to run - which it will until something shuts it off - the carbon brushes and ceramic seal wear rapidly against each other without the water film that normally lubricates them. A pump run dry for more than a few minutes can develop heat damage that shows up as early bearing failure weeks later.
The practical solution is a low-water shutoff sensor in the fresh tank wired to interrupt pump power. Many coaches do not come with one from the factory. Triton RV Repair installs them during pump replacement calls when the coach lacks the protection, at modest additional cost given that the wiring is already accessible.
The Accumulator Tank - How It Works and When You Need One
An accumulator tank is a sealed pressure vessel with a rubber bladder inside. Water fills one side of the bladder and a pre-charged air volume sits on the other. When the pump runs, it charges both the system and the bladder. When a faucet opens briefly, the bladder deflates to supply a small amount of water before the pump cycles - smoothing out the pressure wave and eliminating the rapid on/off that causes most pump wear.
In Florida coach parks and campgrounds, where water pressure at the site can spike and drop with demand from neighboring coaches, an accumulator also buffers those upstream fluctuations from reaching your fixtures. Sinks and showers that used to surge and dribble perform consistently once an accumulator is in the line. Installation takes about an hour and requires no changes to the rest of the plumbing.
Diagnosing the Pump Versus a System Leak
Jesse isolates the pump from the rest of the plumbing by closing the outlet valve and then running a pressure test on the supply side alone. If pressure holds, the pump is fine and the problem is downstream. If pressure drops with the outlet closed, the pump check valve or the pump body itself is leaking internally. This two-step test takes less than five minutes and prevents replacing a working pump.
For coaches without an accessible shutoff between the pump and the distribution manifold - which is most coaches built before 2015 - the pressure test uses the pump's own bypass mode or a temporary test port. The goal is always to confirm the failure before ordering parts, not after.
Service Pricing
| Service | Notes | Typical Range |
|---|---|---|
| Service call + pump diagnosis | Includes pressure test, flow test, and strainer check | $299 - $399 |
| Shurflo 3.5 GPM replacement (installed) | Most common OEM replacement; includes bypass check | $145 - $280 |
| Flojet 4.0 GPM replacement (installed) | Higher-flow; good for coaches with multiple simultaneous draws | $165 - $310 |
| Accumulator tank installation | Reduces pump cycling and extends pump life | $95 - $185 |
| Pressure switch replacement only | If pump cycles but delivers full flow | $65 - $145 |
Pricing transparency: All prices are estimates based on typical coach configurations. Labor-intensive access situations, custom coach layouts, and parts availability affect the final figure. The service call fee of $299 - $399 covers diagnosis, testing, and the first hour of labor.
Triton RV Repair quotes in writing before any repair begins. There is no charge for a recommendation that the repair is not cost-effective.
Frequently Asked Questions
Why does my RV water pump run but deliver no water?
A pump that hums or clicks but moves no water has usually lost its prime. In Florida's heat, flexible tubing between the tank outlet and the pump can develop micro-cracks that admit air without leaking water, and air in the suction line breaks prime completely. The pump spins against nothing and produces no flow even at full speed.
What causes an RV water pump to cycle on and off constantly?
A demand pump cycles because it is doing exactly what it was designed to do: restore pressure the moment pressure drops. If the pressure drops continuously - due to a weeping fixture, a pin-hole in a PEX joint, or a check valve that won't seat - the pump runs every few minutes even with nothing open. This is not a pump failure; it is the pump reporting a system failure.
How long should an RV water pump last?
A quality Shurflo or Flojet pump installed correctly should run 50,000 to 80,000 cycles before any wear-related failure. At typical usage that is five to ten years, but Florida adds variables that compress that lifespan. UV degradation of inlet tubing, mineral deposits from well-fed campgrounds, and the corrosive air near the coast all attack pump internals faster than in dry climates.
Can the water pump damage itself by running dry?
An RV demand pump has no automatic dry-run protection. If the fresh tank runs empty and the pump continues to run - which it will until something shuts it off - the carbon brushes and ceramic seal wear rapidly against each other without the water film that normally lubricates them. A pump run dry for more than a few minutes can develop heat damage that shows up as early bearing failure weeks later.
What is a water pump accumulator and do I need one?
An accumulator tank is a sealed pressure vessel with a rubber bladder inside. Water fills one side of the bladder and a pre-charged air volume sits on the other. When the pump runs, it charges both the system and the bladder. When a faucet opens briefly, the bladder deflates to supply a small amount of water before the pump cycles - smoothing out the pressure wave and eliminating the rapid on/off that causes most pump wear.
Sources and Further Reading
- Shurflo RV pump documentation - 3.5 and 4.0 GPM pump specifications, pressure switch settings, and winterization procedures.
- Flojet RV pump product line - Bypass and self-priming pump specifications and troubleshooting guides.