RV Water System Troubleshooting Guide

No Water at Any Faucet

Pump Short-Cycles (Runs Without Faucets Open)

A pump that cycles on and off every 30–60 seconds with no faucets open means there's a small leak somewhere losing pressure. The pump is trying to maintain system pressure.

• Check every faucet: A slightly open faucet or a running toilet valve is the most common cause — easy fix.
• Check the water heater bypass: If the water heater bypass valves are partially open, water leaks around the heater. Confirm all bypass valves are fully in the correct position.
• Check the toilet flush valve: A toilet that runs slowly (heard as a faint hiss) leaks water into the tank and triggers pump cycling. Replace the toilet foot pedal seal or valve.
• Check the accumulator tank: Many RVs have a small pressurized accumulator tank that reduces pump cycling. If the bladder inside is failed (punctured), the pump short-cycles constantly. Press the Schrader valve on the tank — if water sprays out, the bladder is failed.
• Check outside connections: The low-point drains at the bottom of the RV may be partially open. Also check the fresh tank drain valve.

Low Water Pressure

Low pressure on city water is usually a restriction issue. Low pressure from the pump can indicate a weak pump or blockage.

• City water pressure regulator: Most RVs use a 45–55 PSI pressure regulator on the city water inlet. If yours is adjustable, it may have drifted. A failed regulator can also restrict flow.
• Inline water filter clogged: A partially clogged sediment filter drastically reduces flow and pressure. Replace the cartridge — it's a 5-minute job.
• 12V pump losing power: The pump pulls 3–8 amps at full load. If your 12V system is weak (battery low, bad connection), the pump can't build full pressure. Test pump voltage while it runs.
• Aerator screens clogged: Debris builds up in faucet aerators over time. Unscrew the aerator at the tip of each faucet and clean the screen — this often doubles apparent water pressure.

No Hot Water

RV water heaters run on propane, electric, or both. The troubleshooting path depends on your heater type.

Propane Water Heater (Atwood / Suburban)

1. Make sure the propane supply is on and other propane appliances (stove) work — if not, check your LP tank level and the regulator
2. Check the water heater's door — it must be closed and latched for the unit to operate
3. Reset the ECO (Energy Cut Off) switch — a small red button inside the door behind the burner panel. Push it once and retry
4. Check the electrode gap on the igniter — if it's corroded or the gap is off, the spark won't jump to light the burner
5. Check the thermocouple — this safety device shuts off the gas if the pilot goes out; a failed thermocouple won't let the main burner open

Electric Water Heater Element

If your heater has an electric mode (DSI or dedicated element), check the 120V breaker for the water heater in your main panel. A failed heating element reads as an open circuit on a multimeter (should read 10–20 ohms). Also check the high-temperature limit switch — it's a small red button or disk on the element, similar to the propane ECO button.

Tankless Water Heater (Truma, EcoTemp)

Truma AquaGo and similar units flash error codes. Common error E3 = flow too low; E5 = ignition failure. Ensure adequate water flow before ignition — turn on a faucet fully, then switch on the heater. The unit won't ignite with low-flow demand.

Smelly or Discolored Water

A rotten egg smell from hot water only usually means the sacrificial anode rod in the water heater has reacted with high-sulfur water. Remove and replace the anode rod (threads out with a 1-1/16" socket) and flush the tank. A whole-RV smell indicates the fresh tank needs sanitizing.

Fresh Tank Sanitizing

1. Drain the fresh tank completely
2. Mix ¼ cup of unscented household bleach per 15 gallons of tank capacity with water
3. Pour the solution into the tank, then fill to capacity with fresh water
4. Run water from all faucets until you smell chlorine, then shut off
5. Let sit for 4–12 hours, then drain completely and refill with fresh water twice

Black Tank Won't Drain

A clogged black tank is unpleasant but usually fixable without a service call.

• Pyramid plug: If the tank was drained while partially empty, solid waste builds up into a "pyramid" near the drain outlet. Fill the tank ¾ full with water and drive the RV to slosh the contents before draining.
• Stuck gate valve: The knife valve can stick if it hasn't been opened recently or if solids have dried on the blade. Slowly work it open and closed several times with tank weight helping. A stuck valve may need WD-40 sprayed into the valve body and repeated cycling.
• Frozen outlet: In freezing temperatures, the tank outlet, hose, or sewer connection freezes solid. Use an electric heat tape or pour hot water over the outlet area — never an open flame.

Winterizing & Spring Startup

Winterizing: Drain the fresh tank → drain and bypass the water heater → blow out lines with compressed air (or pump RV antifreeze through) → pour antifreeze down all drains and the toilet bowl → close all low-point drains.

Spring startup: Open all low-point drains to release any trapped antifreeze → reconnect the water heater → fill the fresh tank → run all faucets until antifreeze clears → sanitize the tank → test all appliances.

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RV AI Help provides general information only. Always verify safety-critical repairs with a qualified RV technician. Product links are affiliate links — we may earn a commission at no extra cost to you.