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RV Water Heaters
Tank vs. tankless, the major brands, and the maintenance that matters.
Hot water is one of those things you don't think about until it's gone. This advice comes from what we see come back for repair, not from a single brand's brochure.
QUICK ANSWER
Most RVs have a 6- or 10-gallon tank water heater from Suburban or Dometic (formerly Atwood). Suburban tanks are porcelain-lined steel and need an anode rod; Dometic/Atwood tanks are aluminum and don't. Tankless heaters from Truma, Girard, Furrion and Suburban give continuous hot water on propane, but they need a minimum water flow and 12V power to run.
STEP ONE
Tank or tankless?
Tank · 4 to 16 gal
Tank water heaters
Keep a set amount of water hot and ready, on propane, 120V electric, or both.
+ Simple, proven and easy to service
+ Most run on shore power alone
− A 6-gallon tank runs out mid-shower, then needs time to recover
Tankless · on-demand
Tankless water heaters
Fire a propane burner only when a hot tap opens. Most fit an existing 6- or 10-gallon opening.
+ The hot water doesn't run out
− Need a minimum flow to ignite (about 0.4 to 0.9 GPM)
− Propane only, with no electric mode
− Freeze protection needs propane and 12V on
Low-flow shower heads and tankless don't always mix. If flow drops below the heater's activation point, the burner shuts off and you get a cold "sandwich" in the middle of your shower.
AT A GLANCE
Tankless RV water heaters compared
Model
Max output
Min. flow
12V draw
Notable
Truma AquaGo
60,000 BTU/h
~0.4 GPM
< 2.5 A
Easy Drain lever; optional antifreeze kit to −4°F
Furrion Tankless
60,000 BTU
GPM not published
Amps not published
Rated 2.4 GPM; built-in antifreeze protection
Suburban ST-60
8,000–60,000 BTU/h
0.7 GPM
< 10 A
95–131°F; ST-42 version up to 42,000 BTU/h
Suburban Advantage Tankless
15,000–60,000 BTU/h
GPM not published
Amps not published
0.5-gallon buffer tank smooths temperature swings
Girard GSWH-2
42,000 BTU
0.8–0.9 GPM
< 3 A
Wall panel, 95–124°F
"Not published" means the manufacturer doesn't list that figure. Gallons per minute at a given temperature depends on how cold the incoming water is, and most makers don't publish it. Specs are from each manufacturer's product pages and manuals.
THE BRANDS
Who makes RV water heaters
Suburban
Airxcel · owned by THOR Industries
Advantage tanks in 4, 6, 10, 12 and 16 gallon. The SW6D is 12,000 BTU/h with direct spark ignition and an optional 1,440 W element
Direct Fit SAW6D drops into a 6-gallon Atwood/Dometic opening
Tankless: ST-42, ST-60 and Advantage Tankless
Porcelain-lined steel tank: needs an anode rod
Dometic (Atwood)
Bought Atwood in 2014 · rebranded 2017
WH-6GA: 6-gallon, gas, 10,000 BTU
WH-9GEA XT: 6-gallon, gas/electric
New for 2026: an all-electric 6-gallon, 1,400 W heater that mounts inside with no exterior vent
Aluminum tank: no anode rod
Girard
Lippert
GSWH-2 tankless: 42,000 BTU, under 3 A on 12V
Adjustable from 95 to 124°F at a wall panel
Fits existing tank cutouts; Lippert sells door kits, including one for Atwood/Dometic openings
An easy retrofit from a tank unit
Furrion
Lippert
Tankless gas: 60,000 BTU, rated at 2.4 GPM
Built-in antifreeze protection and a wall thermostat
Designed to retrofit existing tank openings
High output for its size
Truma AquaGo
Truma
Modulates from 20,000 to 60,000 BTU/h
The lowest activation flow here, about 0.4 GPM
Tool-free Easy Drain lever and a decalcification mode
Optional antifreeze kit protects to −4°F
KEEP IT RUNNING
RV water heater maintenance that matters
1
Never fire it dry
An empty tank destroys the electric element in seconds, and Suburban's warranty doesn't cover it. Run a hot faucet until water flows steadily first.
2
Check the anode every year
Suburban says to replace it yearly, or when more than 75% is gone. Running without one voids the tank warranty. Atwood/Dometic tanks don't use one.
3
A dripping relief valve is usually normal
Water expands as it heats. Draining the tank restores the air pocket that absorbs it. A steady stream or scalding water is not normal.
4
Winterize with the bypass
Keep RV antifreeze out of the tank; it eats Suburban anodes. Tankless units use compressed air, a drain lever or the maker's antifreeze mode.
WHERE TO BUY
Where to buy RV water heaters and parts
Water heater parts aren't universal, so the right store is the one that can match your exact model. Here's where RV owners commonly buy, and what each is good for:
Store
Type
Brands seen in stock
Good for
RV water heater specialist
Suburban, Dometic/Atwood, Girard, Fogatti
Water heaters and parts matched to your model
Online marketplace
Suburban and Girard parts from third-party sellers
Common parts; check who the seller is
Your local RV dealer
Service department
Varies
Installation, warranty work and same-day pickup
Free help before you buy: manuals from the Suburban manual library, Dometic, Lippert (Girard and Furrion) and Truma, and owner forums like iRV2. Store details checked October 2026.
QUESTIONS
RV water heater FAQ
Do Dometic and Atwood RV water heaters need an anode rod?
No. Atwood and Dometic tanks are aluminum and are built without an anode rod. Suburban tanks are porcelain-lined steel and do need one.
What replaces a discontinued Atwood water heater?
Most Atwood models were folded into Dometic in 2017. The usual options are a current Dometic model such as the WH-6GA or WH-9GEA XT, Suburban's SAW6D Direct Fit for 6-gallon openings, or a tankless heater with a door kit sized for Atwood/Dometic openings, such as Girard's.
Can a tankless RV water heater run on shore power alone?
No. RV tankless units burn propane and need 12V DC for their controls and fan. A tank heater with an electric element is the option that can run on 120V shore power alone.
Why does my tankless water heater go cold mid-shower?
The water flow probably dropped below the heater's minimum activation flow, which is about 0.4 GPM for Truma and 0.7 to 0.9 GPM for Suburban and Girard. Low-flow shower heads and partly open taps are the usual causes.
Why is my RV water heater relief valve dripping?
A small drip while the water heats is normal: heated water expands in a closed system. Draining the tank restores the air pocket at the top that absorbs the expansion. A steady stream or very hot water is not normal and should be checked.
How do I find my RV water heater model?
Look for the data plate, usually behind the exterior access door. It lists the brand, model and serial number you need to order the right parts.
REPLACING A HEATER OR BUYING PARTS?
Start with your data plate
Gas valves, control boards, elements, doors and anodes vary by model. RV Water Heater Guys stocks new water heaters and replacement parts for Suburban, Dometic/Atwood and Girard, plus Fogatti tankless units, and will help you match the right part.