Cold shower at the campsite because your RV water heater quit? Before you pull panels, run through this checklist — most failures come down to four causes you can rule out in minutes.
Nothing kills the morning campsite vibe like turning on the shower and getting a face full of ice water. You hit the switch, you waited — and still nothing. Before you start pulling panels off and regretting your choices, let's actually diagnose this thing. Most RV water heater failures come down to four or five causes, and you can rule them out in about five minutes.
RV water heaters run on propane, electricity, or both. The fix depends entirely on which mode failed and why. Let's break it down.
First: Figure Out Which Mode Failed
Most RV water heaters (Atwood, Suburban, Dometic) have a switch panel inside — usually near the kitchen or in a dedicated control panel. There's typically an “Electric” switch, a “Gas” switch, or both. If you're on shore power, try electric. If you're dry camping, you're running propane. If one mode doesn't work, try the other before assuming the worst.
Before anything else — check the bypass valve
If you had your RV winterized, there's a bypass valve that routes antifreeze around the water heater. If it's still in bypass mode, hot water will never reach your fixtures no matter how well the heater works. It's a two-second check on the side of the tank — look for a valve handle perpendicular to the pipe. If it is, rotate it parallel to open the flow.
Electric Mode Not Working
If the electric element isn't heating, start here:
Check the breaker
Your water heater has its own dedicated breaker in the main panel. A tripped breaker is the #1 cause of "the electric isn't working" calls we get. Reset it and see if it immediately trips again — if it does, that's a short, not a breaker issue.
Check the ECO (Energy Cut-Off) switch
There's a small red reset button on the water heater itself — often behind the exterior access panel. It's a thermal fuse that trips when the tank overheats. Press it firmly until you feel a click. This is more common than people think.
Test the heating element
If the breaker is fine and the ECO is reset but still no heat, the element itself may have burned out. They're replaceable and cost around $15-30 — but you need a multimeter to confirm it's actually dead before buying parts.
Propane Mode Not Working
Gas-side failures are a little more involved. Here's the checklist:
- Confirm your propane tank has fuel — sounds obvious, but we've made the drive to "fix" water heaters that just needed a refill.
- Make sure the propane valve at the tank is fully open. A quarter-turn closed will cut flow to everything.
- Check if other propane appliances work — if the stove lights but the water heater doesn't, the issue is specific to the heater.
- Look for the pilot light status light or listen for the igniter clicking. If it's clicking but not lighting, there may be air in the line — try igniting it 3–4 times in succession.
- Inspect the sail switch or vacuum switch. These safety devices confirm adequate airflow before allowing the burner to fire. Dust, spider webs, or a stuck float can prevent them from signaling correctly.
The Unit Is Running But Water Isn't Hot Enough
Lukewarm water when you expected hot usually points to one of three things:
- Sediment buildup in the tank — mineral deposits insulate the element from the water. Flushing the tank annually (there's a drain plug on the exterior panel) extends element life and improves efficiency.
- A partially failed heating element — it's heating, but not at full wattage.
- The thermostat is set too low — some RV water heaters have an adjustable thermostat behind the access door. Factory setting is often around 120°F, which isn't impressive. Some techs bump it to 130–140°F.
Common Question
How long should it take for my RV water heater to heat up?
A 6-gallon Suburban or Atwood on propane should reach temperature in about 20 minutes from cold. On electric, expect 45–60 minutes for the same tank. If yours is taking significantly longer, sediment buildup or a weak element is the likely culprit. On propane, slow heating often points to low gas pressure or a partially blocked orifice.
Most RV water heater problems are fixable — the ECO reset, a tripped breaker, or a simple bypass valve are all five-minute calls. But when the igniter is clicking with no flame, there's a gas smell, or the element keeps burning out, that's when you stop Googling and pick up the phone. We carry parts and we come to you.
BossBros RV Team
Redding, CA