Not sure how to drain an RV water heater? No problem, we’ll walk you through this step by step. The offseason is a great time to catch up on maintenance to reduce the chance of issues arising during the camping season. Draining your RV water heater should be at the top of the list. It’s fast and easy and can help save you from a costly repair down the road.
Let’s cover the importance, recommended frequency, and steps for this important RV water heater maintenance task.
Why Do You Need to Drain an RV Water Heater?
There are several reasons to drain an RV water heater: cleaning, sanitizing, and winterizing.
Cleaning
Seasonal cleaning is the primary reason to drain RV water heaters that contain a RV water heater anode rod. The rod contains various metals that break down inside the tank to prevent corrosion. As the rod breaks down, sediment is left behind.
Calcium buildup can also occur in addition to anode rod particles. This is true for water heater tanks with and without a sacrificial anode rod. These sediments must be cleared to avoid clogging plumbing lines, faucets, or showerheads.
Technician Tip: There won’t be an anode rod if you have an aluminum tank.
Sanitizing
In addition to draining sediment, you should periodically sanitize RV fresh water tanks. Sanitizing your tank keeps your water clear and helps knock loose stuck sediments. It’s also a great way to get rid of lingering smells.
Winterizing
If you live in a climate with freezing temperatures, you must drain your tank at the end of every season. As water freezes, it expands, which could damage your tank and or water lines. This is why draining the tank and winterizing the lines with antifreeze is necessary. However, antifreeze shouldn’t be pumped into your water heater tank, as it can neutralize the anode rod’s reactive metals, increasing the chances of internal tank corrosion and failure.
How Often To Drain RV Water Heater
Your RV water heater should be drained and serviced at least once a year, depending on how often and frequently you use it. If you’re a full-timer, you might want to do this more frequently, but if you only camp a few times a year, annual water heater service is a smart idea. If your camper sits for long periods of time in between trips (two weeks or more), more frequent drainings are recommended.
How To Drain Water Heater on RV
Although the draining procedure for most water heaters is similar, there can be some differences. For example, how to drain a Dometic RV water heater can be slightly different than how to drain a Suburban RV water heater. That’s why it’s important to reference your specific water heater’s owner’s manual before getting started.
To get started, you’ll need a few tools, mainly a drain plug wrench. An adjustable crescent-style wrench may work for this unless your drain plug is in a tight space (most are); in this case, you may need a socket with an extension or an RV water heater drain plug wrench.
Technician Tip: The drain is not always at the tank’s lowest point, so there is still a chance for water and sediment to collect at the bottom. To drain the tank completely, use a water heater tank rinser to clear the remaining water and debris.
It’s smart to have a bucket to catch water if you’re in an area where it cannot drain onto the ground, but odds are some water will escape regardless.
- Turn off the power to the water heater. Depending on your model, there can be multiple switches, and these switch locations can vary. Start by looking inside the trailer for wall switches or breakers in the main panel. Then, take the service cover off the exterior wall and look for switches inside to disconnect.
- Run the hot water faucets with the water heater turned off until the water temperature has dropped to a safe level.
- Disconnect city water (if equipped) and remove power from the RV water pump (see fuse panel or wall switch).
- Open the pressure relief valve on the tank by lifting the handle.
- Using an appropriately sized tool, remove the drain plug and let the tank drain completely. (For some models, the drain plug can also double as the anode rod.)
Technician Tip: If water flow seems restricted when draining, use a rinsing wand or a dull plastic probe to remove any obstructions from the drain hole. Be careful not to scratch the tank’s inner lining. A sediment blockage at the drain opening can be removed with a metal probe, but a non-marring tool can be substituted to prevent the possibility of unintended damage from a hard or sharp edge. City water pressure can be used to rinse the tank so long as it is applied after the drain plug has been safely removed. It should not exceed 80 PSI to prevent the debris leaving the tank from traveling at dangerous speeds, risking injury or damage. The city water pressure method is more difficult to control and may be less effective than a curved wand.
Cleaning and Sanitizing an RV Water Heater
Once the tank is empty, you can begin cleaning and sanitizing.
- Close the pressure relief valve and turn the water supply back on.
- Allow the tank to flush for a few minutes.
- Turn off the water and reinstall the drain plug.
- Using a winterization kit, pump white vinegar into the water heater tank.
- Let the vinegar sit for a few hours.
- Remove the drain plug, turn on the water, and let the system flush for a few more minutes.
- Reinstall the plug with plumber’s tape and resupply power.
Once you have finished cleaning and sanitizing, replace your anode rod if the wear is beyond the manufacturer’s specifications.
Where Is the RV Hot Water Tank Drain Plug?
The hot water tank plug location can vary by manufacturer and model, but most are near the bottom of the tank, accessible through the exterior service door. Below is a photo of the drain plug shown on two common RV water heaters, Dometic and Suburban. If you can’t find yours, reference your water heater’s owner’s manual for the exact location.
What Size Is the Drain Plug on RV Hot Water Heater?
Depending on the water heater manufacturer, you’ll need anywhere from a ⅞” to 1-1/16” socket to remove the drain plug. While ⅞” and 15/16” sockets are common in most sets, larger sockets typically must be purchased separately. This larger bolt head size is why some RVers use an adjustable wrench to remove their water heater’s drain plug. However, that comes with the added risk of damaging the plug or other components. Purchasing the correct socket with an extension or using a water heater wrench are your best methods for removing a water heater’s drain plug.
Hopefully, you feel confident to tackle your next water heater maintenance project. If not, no worries—we have a service center near you to help. Check out some of these other great articles on RV water heaters:
- Why Is My RV Hot Water Heater Not Working?
- What to Look For In a Tankless RV Water Heater
- Eccotemp Tankless Water Heater Review
Let us know in the comments below if you’ve ever drained the tank on your water heater and how it went!
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