How to Replace an RV Water Pump

By RVTroubleshoot Staff — A weak or noisy RV water pump can ruin an otherwise peaceful weekend. The good news? Replacing it is a straightforward DIY job that takes less than an hour if you’ve got basic tools and patience.

Don’t let the “plumbing” part intimidate you — these 12V pumps are built to be serviceable. The hardest part is usually just reaching them.

When to Replace Your Water Pump

Most RV pumps last 3–5 years depending on how much you travel and whether you winterize properly. Common signs it’s time for a swap:

The pump cycles on and off constantly, even with faucets closed.
You hear loud chattering or grinding noises.
Water flow pulses or drops under normal pressure.
It’s leaking at the housing or fittings.

Tools & Supplies

New 12V water pump (match brand/model or flow rating)
Screwdrivers and pliers
Adjustable wrench
Towels or small catch pan
Pipe tape or thread sealant (if threaded fittings)
Crimp connectors or butt splices (for wiring)

Before You Start

Disconnect power from your RV (turn off 12V master or remove the fuse).
Open a faucet to relieve pressure in the system.
Close your fresh water tank valve or disconnect city water.

Step-by-Step Replacement

1. Locate the Pump

Most pumps are near the freshwater tank or under a bed, cabinet, or step. Follow the suction line from the tank if you’re unsure. Clear space around it before starting.

2. Disconnect Water Lines

Place a towel or small pan beneath the pump. Loosen both the inlet and outlet fittings. A small amount of water will spill out. Keep the fittings handy — most pumps reuse them.

3. Disconnect Wiring

Note the polarity: red is positive, black is ground. Cut or unplug the wires, depending on your setup. If you’re cutting, leave yourself enough slack to reconnect easily.

4. Remove the Pump

Unscrew the mounting screws and pull the pump free. Some models are mounted to rubber isolators — save those to reuse, as they reduce noise.

5. Prep the New Pump

Attach the same fittings or new ones (using pipe tape if threaded). Make sure the flow direction matches your old setup — most pumps are labeled “IN” and “OUT.”

6. Install & Reconnect

Mount the pump securely. Connect the inlet and outlet lines, tightening snugly but not over-tight. Crimp or reconnect the wires (red to positive, black to ground). Secure them neatly out of the way.

7. Test & Inspect

Restore 12V power. Open a faucet and let the pump prime — it’ll run for a few seconds to fill the lines. Once the air is out, it should shut off. Check for leaks or drips, then tighten as needed.

A good pump should hold pressure silently. If it cycles occasionally with no water use, you may have a small plumbing leak downstream.

Maintenance Tips

Drain the system before winter to prevent cracking the housing.
Clean or replace the pump’s inlet strainer once a season.
Run it monthly even during storage to keep the diaphragm lubricated.

Final Word

Replacing your RV water pump isn’t complicated — it’s one of those confidence-building jobs that makes you feel more in control of your rig. A quiet, steady stream of water is a small reward for an hour’s worth of work, and you’ll never hesitate to tackle it again once you’ve done it yourself.