RV Water Heater Troubleshooting Guide: Fix It Fast

Quick Diagnosis: Where to Start

Before diving into specific causes, run a quick diagnostic. First, check your water heater's display panel or manual for error codes—they narrow down the issue dramatically. Second, verify that your RV has shore power or a charged battery (most modern heaters won't ignite without electrical power, even gas models).

Third, confirm propane flow by checking your tank gauge and listening for the hiss of propane when you turn on a stove burner. Fourth, set your thermostat to at least 120°F and wait 5 minutes to allow the heating element to warm. If you see or smell anything unusual (rotten egg smell, which indicates propane odor additive, is normal if there's a leak), stop and ventilate immediately.

Keep these three facts in mind: electric heating elements burn out most often; pilot lights fail due to airflow or igniter electrode corrosion; gas and electric modes are independent, so one can fail while the other works. Once you've ruled out obvious issues, move to the cause-specific sections below.

Not Heating at All: Gas and Electric Modes

If you have hot water sometimes but not always, or never, start here. Most RV water heaters have both gas and electric modes, and each has independent failure points. " Many owners forget to switch modes or leave it in Auto when it's not working.

Second, look at the thermostat: it should be set to at least 120°F, and the heating should turn on within 5 minutes. If nothing heats after waiting, try toggling the mode (switch from Gas to Electric or vice versa) to confirm the other mode works. If only one mode works, that narrows your problem.

Third, confirm electrical power is reaching the unit. Check the breaker panel for a tripped breaker (look for any switch that's in the middle or off position), and flip it back to on. If it trips again immediately, there's an electrical fault and you need professional help.

For gas mode, confirm the propane tank has fuel by listening for gas at other appliances. If nothing heats in any mode, the control board or thermostat may have failed entirely—this requires replacement.

Pilot Light or Igniter Not Lighting

This is the most common RV water heater complaint and often fixable. If your heater makes a clicking sound when you turn on the gas but doesn't ignite, the igniter electrode isn't firing or the igniter itself is faulty. Start by checking for propane: listen at your propane stove—if other appliances have gas, your tank isn't the issue.

Next, visually inspect the igniter electrode (consult your manual for exact location; it's usually a thin ceramic rod near the burner). If it looks covered in white crusty deposits or is corroded, gently clean it with very fine sandpaper or a pencil eraser—be extremely gentle to avoid cracking the ceramic. Wipe away all dust and reinstall.

Try lighting again. If the electrode is cracked or broken, it needs replacement (typically $30–$80 part). If cleaning helps and you light successfully, the cause was corrosion from moisture or mineral deposits.

If clicking continues without ignition, the DSI (Direct Spark Ignition) board may have failed and won't deliver spark, or the thermocouple is bad and killing power to the igniter. Both require professional service. Atwood and Suburban models are prone to electrode corrosion in humid climates; keep spares on hand if you're in the Southwest or near salt water.

Works on Gas but Not Electric (or Vice Versa)

If your heater works perfectly on gas but electric mode produces no heat (or vice versa), you have a mode-specific failure. For electric-only failure: First, confirm the heating element is getting power. Check that the thermostat is set above 120°F and the electric mode is selected.

If you can hear a faint hum or feel slight warmth from the tank but water never gets hot, the heating element is likely burned out and needs replacement (a $100–$200 part, plus $150–$300 labor for professional installation). If there's no hum or warmth at all, the element may be completely dead or disconnected. For gas-only failure: Confirm propane is flowing (test at another appliance).

If gas flows everywhere else but not the heater, the propane solenoid valve on the heater unit has failed and won't open—this requires a technician because it involves pressurized propane. If gas ignites but doesn't reach full temperature, the gas burner orifice may be clogged (mineral buildup or propane gum), and you'll need to remove it and have it professionally cleaned. Mode-specific failures are never simple—either the heating element burned out (electric) or the solenoid/burner mechanism failed (gas).

Don't attempt to repair these yourself; get a technician involved.

Leaking Water from the Heater Tank

Water dripping or pooling under your RV water heater demands immediate attention to prevent structural damage. Start by identifying where the leak originates. Is it coming from the tank itself, from a connection, or from a pressure relief valve?

An anode rod is designed to sacrifice itself to prevent rust; if your tank is leaking around the anode rod hole (usually at the bottom), the tank is corroded and can't be saved—replacement is necessary. However, if the leak is from a connection (inlet, outlet, or relief valve), it may be a loose fitting. Try tightening the fitting with a wrench (turn clockwise, but don't over-tighten or you'll crack it).

If tightening doesn't stop the leak, the fitting needs new plumber's tape or thread sealant. For pressure relief valves (typically on top or side of tank), a slow drip is normal in warm weather (it's supposed to release excess pressure), but continuous heavy leaking means the valve is stuck open and needs replacement. If you're seeing steady water loss from the tank body itself and the anode rod isn't the cause, the tank has pinhole rust holes and cannot be repaired.

You must replace the entire water heater (typically $400–$1000 for the unit). Dometic and Norcold models older than 15 years are especially prone to rust if the anode rod was never serviced. Check inside the tank annually and replace the anode if corroded.

Brand-Specific Issues: Atwood, Suburban, and Dometic

Different manufacturers have well-documented weak points. Atwood (most common in budget RVs) heaters fail most often due to igniter electrode corrosion in humid climates and DSI board failures after 5–10 years. If you own an Atwood, keep a spare electrode on hand and consider replacing the anode rod every 2–3 years.

Suburban models are generally robust but suffer from thermostat creep (the dial gets loose and readjustment is needed) and occasional heating element burnout in units over 8 years old. Dometic (premium brand) is reliable but parts are expensive; their electronic control boards are prone to failure in RVs stored outside in extreme heat or cold, and if your Dometic won't ignite despite good propane and power, the board usually needs replacement ($200–$400 part). Norcold heaters (also premium) rarely fail outright but are notorious for very slow heating times compared to competitors—this is normal.

All brands benefit from annual flushing to remove sediment buildup that reduces heating efficiency. If you don't know your brand, check the label on the tank or look in your RV's maintenance manual. Knowing your manufacturer helps you anticipate common failures and parts costs.

When to Call a Professional RV Technician

Stop troubleshooting and call a certified RV technician if any of the following apply: (1) you smell propane but the heater won't ignite—a propane leak near the heater is dangerous; (2) the tank is actively leaking from the body or any connection and simple tightening didn't help; (3) your DSI board is dead (clicking but no spark) or your thermostat is unresponsive to adjustment; (4) your heating element is burned out or the electric solenoid is dead; (5) you've reset breakers and cleaned electrodes, but nothing works. Professional replacement or repair typically costs $150–$500 in labor plus parts, but attempting a complex repair yourself (like soldering corroded connections or replacing a solenoid) risks propane leaks or electrocution. Always prioritize safety over saving money.

If you're unsure whether you've fixed the problem, turn off the heater, cool it down, and have a tech inspect before using it again.