RV Water Heater Repair: What to Check Before You Call Anyone

Most RV water heater problems are not repairs at all. They are a reset button, a tripped breaker, or a tank full of sediment. The genuinely broken ones are rarer than the forums suggest, and most RV water heater repair jobs come down to ten minutes of checking in the right order.

There is one thing worth knowing before any of that, because it changes what you are allowed to do to your own water heater, and getting it wrong can put a hole in the tank. It is covered two sections down, and it is the part most articles on this subject get flatly wrong.

Why Is My RV Water Heater Not Working?

Work through these in order. The order matters, because each one is cheaper and more likely than the one after it, and RV water heater troubleshooting done out of sequence usually ends with somebody buying a part they did not need.

Is it on? Both switches. Most rigs have one inside on the wall panel and, on gas and electric models, a second one for the electric element. Owners routinely flip the inside switch and forget the heater has been in electric mode since the last campground.

Is there propane getting to it? Light a stove burner. If the burner lights and holds a steady flame, you have gas at the appliance and the problem is downstream. If the burner sputters, the problem is the tank, the regulator, or a valve, and the water heater is innocent.

Is the bypass still closed? If you winterized, the bypass valves send water around the tank instead of through it. The heater then runs on an empty or half empty tank and either will not light or heats nothing. This is the single most common cause of a water heater that stopped working over the winter, and it is not a fault at all.

Is the tank actually full? Open a hot tap and let it run until water flows steadily. Air in the tank is normal after storage and takes a minute to clear.

Has it locked out? Gas models attempt ignition a set number of times and then stop trying. Until you reset it, nothing will happen no matter what else you fix.

If all five check out and there is still no hot water, you have a real fault, and the next sections narrow it down.

Is Your Tank Aluminum or Steel? Check Before You Touch Anything

This is the fork in the road, and it decides whether your heater needs an anode rod or must never have one.

Dometic, formerly Atwood, uses aluminum tanks. Dometic states that their water heater tanks are constructed of a high strength aluminum, and that the aluminum is anodic to heavy metals and acts much like an anode rod in a steel glass lined tank, except that it lasts much longer.

Their instruction on the subject is not a suggestion. Dometic writes: do not use aftermarket anode rods, because doing so can damage the tank.

Suburban uses porcelain lined steel. Suburban describes its Advantage water heaters as having a porcelain lined steel tank, and states that the tank is protected by a magnesium or aluminum anode to prolong the life of the tank.

So the same component is essential on one brand and damaging on the other. An aluminum tank is built to resist corrosion on its own, which is why it leaves the factory without a rod and without a port to put one in.

How to tell which you have without guessing. Look at the drain. A Suburban steel tank drains by removing the anode rod itself, which is a large hex plug. A Dometic aluminum tank has a small plastic drain plug instead. If you are looking at a plastic plug, do not go shopping for an anode rod.

Why Is My RV Water Heater Clicking But Not Lighting?

Clicking means the board is trying. The igniter is sparking, so the board has power and has decided conditions are right. What it is not getting is a flame it can confirm.

Air in the gas line. After a tank swap or a long spell unused, the line has to purge before gas reaches the burner. Run a stove burner for a minute first, then try the heater again. This fixes it more often than anything else on the list.

A blocked burner tube. Mud daubers build nests inside the burner tube in a single season. The tube is the horizontal pipe running from the gas valve to the burner, and a nest in it stops gas reaching the flame no matter how well everything else works. This is the most common genuine fault on a heater that has been parked outdoors.

A dirty or misaligned electrode. The spark has to jump in the right place to light the gas, and the sensor has to sit in the flame to prove it lit. Soot, corrosion, or a knock during travel moves it out of position.

A failed gas valve. Least likely, and the only one on the list that is a parts job.

Why Is My RV Water Heater Only Lukewarm?

Lukewarm is a different fault from cold, and it usually means the heater is working but something is diluting or limiting it. It is the most common RV water heater repair call that turns out not to be a repair at all.

You are on electric only. The electric element is much slower than the gas burner. On a gas and electric model, running electric alone gives you a tank that recovers slowly and runs out fast.

The bypass is partly open. A bypass valve that has not been turned fully back after winterizing lets cold water join the hot on its way to the tap. The symptom is water that is warm at first and never gets properly hot.

Sediment is insulating the bottom of the tank. A layer of scale between the burner and the water means the burner heats the scale rather than the water. This one builds gradually, which is why it reads as the heater getting tired rather than as a fault.

The thermostat is failing or set low. Worth checking last, because it is the answer people reach for first and is rarely the cause.

How Do I Reset My RV Water Heater?

There are two resets and people confuse them.

The gas lockout reset. After a set number of failed ignition attempts, the control board stops trying and shows a fault. Turning the heater off at the switch, waiting a moment, and turning it back on clears the lockout and starts a fresh ignition sequence. If it locks out again immediately, stop resetting it and work through the clicking section above, because you are re-running a failure rather than fixing one.

The electric element high temperature cutoff. This is a physical button, usually red, on the face of the heater behind the outside access door. It trips when the element runs dry or overheats, and it stays tripped until you press it.

A cutoff that trips repeatedly is telling you something. The usual reason is the element being switched on with the tank empty or bypassed, which damages the element. Pressing the button again and again without asking why is how a slow problem becomes a replacement.

Does My RV Water Heater Need an Anode Rod?

Only if the tank is steel. See the section above, because this is the question where the wrong answer is expensive.

On a Suburban steel tank, the anode rod is not an accessory. It is a sacrificial piece of metal that corrodes so the tank does not, and a tank left running without one is quietly consuming itself instead.

How Often Should the Anode Rod Be Replaced?

Suburban is more specific than the usual advice to check it now and then. Their guidance is that replacement is recommended when consumption or weight loss is greater than 75 percent, and separately that it be replaced yearly.

Suburban’s own service manual puts a number on it: replacement is recommended once the rod has lost more than 75 percent of its material. That is the threshold to judge against, rather than a calendar date.

The practical version: pull it when you winterize, since you have to remove it to drain the tank anyway, and look at it. A rod eaten down to a thin core with the steel wire showing through has done its job and is no longer doing it. Water chemistry decides the rate, so a rod that lasts two seasons in one region will be gone in one somewhere else.

Magnesium or Aluminum Anode Rod?

Suburban accepts either, describing the tank as protected by a magnesium or aluminum anode.

The working difference is that magnesium is more reactive. It protects harder and wears out faster, and in some water it produces a sulfur smell as a side effect. Aluminum lasts longer and is the usual answer if you have had the rotten egg smell before. Neither is wrong, and if you have no smell problem, the choice barely matters.

What Is the Most Common Cause of Water Heater Failure?

Sediment, and the thing about sediment is that it does not announce itself. It reduces capacity, it insulates the burner from the water, and on a steel tank it sits on the bottom holding moisture against the lining.

An annual flush is the whole of the maintenance most RV water heaters ever need. Drain the tank, then use a wand to break up what settled at the bottom, because draining alone leaves the sediment where it is. On a Suburban, the drain is the anode rod itself, which is why flushing and checking the rod are the same job done once a year.

What You Need to Do These Jobs Yourself

Four things, matching the jobs above. Nothing here has been used by anyone at Restful RV, so what follows is about fitment, materials and design rather than how it felt in the hand.

Restful RV is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

How Long Should an RV Water Heater Last?

There is no single honest number, and any article giving you one is guessing. What actually decides it is whether the anode rod was maintained on a steel tank, the water chemistry it has lived on, whether it was drained before a freeze, and how often the element ran dry.

A tank that is leaking from the tank itself, as opposed to from a fitting, is finished. There is no repair for a perforated tank and no sealant that belongs anywhere near one.

What Can You Fix Yourself, and What Needs a Technician?

RV water heater troubleshooting splits cleanly in two, and the line is worth knowing before you start.

Reasonable to do yourself: resets, flushing, anode rod replacement on a steel tank, clearing a wasp nest from the burner tube, replacing a pressure relief valve, and checking bypass valves, which is also where the sewer hose setup starts, the same ones worth watching when you winterize and hang a freeze alarm on the plumbing.

Get a technician: anything involving the gas valve, the control board, or the propane supply beyond turning it on and off. Also anything where you can smell gas, which is not a diagnostic exercise.

The line is not about difficulty. It is that a mistake on the water side makes a mess, and a mistake on the gas side does not. That is the one rule worth carrying into any of the RV water heater problems above.

Frequently Asked Questions

Why does my RV water heater work on gas but not electric?

The high temperature cutoff has almost certainly tripped, or the element has failed from running dry. Check the reset button behind the outside access door first.

Can I run the electric element while the tank is bypassed?

No. The element needs water around it. Running it dry is the most common way an element is destroyed.

Do I need to drain the tank every time I store the RV?

Any time it may freeze, yes. A frozen tank can split, and a split tank cannot be repaired.

My water smells like rotten eggs. Is the heater broken?

No. That is usually a reaction between a magnesium anode rod and bacteria in the water. Switching to an aluminum rod, on a tank that takes one, normally settles it.

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