A leaky RV water heater can put a serious damper on your travel plans—not to mention your floors. Whether it’s a steady drip, a slow seep, or a sudden spray, water heater leaks are not something to ignore. Left unresolved, they can lead to costly water damage, mold growth, and even structural issues in your RV.
Let’s break down the most common causes of RV water heater leaks, how to diagnose them, and what you can do to fix the issue before it gets worse.
Loose or Damaged Drain Plug
The drain plug (or anode rod, depending on the model) is located near the bottom of the tank and is essential for draining and maintaining the heater. Over time, it can become loose, cracked, or stripped—especially after multiple seasons of draining and refilling.
What to Do:
- Check for visible drips around the drain plug when the heater is operating.
- Tighten the plug using a wrench, but avoid overtightening.
- If it’s damaged or leaking from corrosion, replace the plug or anode rod with a new one, making sure it’s the correct size for your heater model.
Faulty Pressure Relief Valve
The pressure relief valve (T&P valve) is a safety mechanism that releases water if the tank pressure gets too high. If this valve is malfunctioning, it may leak even under normal conditions.
What to Do:
- Inspect the T&P valve and discharge tube for any dripping.
- Open the valve manually to flush out debris—sometimes buildup prevents a tight seal.
- If it continues to leak after flushing, replace the valve.
NOTE: Never plug or block this valve. It’s there for your safety.
Cracked Tank from Freezing
If your RV water heater wasn’t properly winterized, any residual water inside could freeze and expand, cracking the tank or internal components. This often results in large, sudden leaks when the system is refilled in spring.
What to Do:
- Look for signs of tank rupture or pooling water under the unit.
- Unfortunately, a cracked tank typically requires full replacement of the water heater.
- To prevent this, always winterize your RV properly, especially before long-term storage.
Leaky Fittings or Connections
Water lines connected to the water heater can loosen over time from vibrations on the road or age-related wear. Fittings may also degrade, crack, or develop pinhole leaks.
What to Do:
- Inspect all inlet and outlet connections for dampness, corrosion, or water streaks.
- Tighten any loose fittings with a wrench.
- Replace worn or cracked lines, fittings, or gaskets.
- Use plumber’s tape or thread sealant on reinstalled fittings to ensure a snug seal.
Internal Corrosion
Older RV water heaters—especially those made of steel—can develop rust and corrosion inside the tank, eventually eating through the walls and causing leaks. This is more common in units that haven’t had regular anode rod replacements.
What to Do:
- If rust-colored water or flakes come from your hot water tap, internal corrosion is likely.
- Drain and inspect the anode rod; if it’s heavily corroded or missing, your tank may already be compromised.
- Replace the water heater if corrosion has eaten through the tank walls.
Overpressurization from the RV Water Pump
An overactive or misadjusted RV water pump can generate too much pressure in the water lines and heater, stressing valves and joints to the point of leaking.
What to Do:
- Monitor your water pressure with an inline pressure gauge.
- Adjust or replace the water pump pressure switch if it’s set too high.
- Consider installing a pressure regulator to protect your system.
Compromised Seals or Gaskets
The seals around heating elements, access panels, or temperature sensors can degrade over time, letting water escape.
What to Do:
- Remove the access panel and check for any moisture around gaskets or wiring ports.
- Replace cracked or compressed gaskets using a manufacturer-recommended replacement.
- Clean the mating surfaces thoroughly before installing new seals.
Stay Ahead of Leaks
Regular inspections and timely maintenance are your best defense against RV water heater leaks. Catching small issues early can prevent major damage down the road.
Need Professional Help? We’ve Got You Covered.
If you’ve spotted a leak or just want a second opinion, JBRV’s expert mobile RV repair team is here to help. We can diagnose and fix your RV water heater leak on-site, whether you’re at home, at the campground, or somewhere in between.
Schedule Your Mobile RV Water Heater Repair today and keep the hot water flowing!