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Fresh water expansion tank failure

My tank started leaking at the metal bands that hold it on the wall in my 98 U270. After getting a camera behind the tank it was fairly straight forward to remove it. I plugged the line and removed the tank. I was astonished to find the tank full of nasty rusted water. It's a two gallon Jabsco 18810-0000. It costs about $230. A Water Worker HT-2B is a quarter of the cost and same size, but reviews indicate it rusts out quickly, sometimes in less than a year.

I had not ever seen rusted water coming out of the faucets. Fortunately we filter all our drinking and cooking water. Is it common for these to be filled with rusty water?  The pump seems to operate well without it, it's a Seaflow 3.0 GPM self priming pump that has been installed for about two years. We always operate from the fresh water tank, so it gets lots of use. I'm pretty sure this tank is original to coach.


1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Fresh water expansion tank failure

Reply #1 –
They definitely do fail. Usually the bladder fails. When mine failed I noticed that the pump sounded different than usual. If you push the air valve pin on the tank and get water instead of air it's time to replace the tank. I got one at Home Depot for around $125.

Sounds like your bladder had been leaking for a while.

The Home Depot Logo
1993 U300 40ft GV SE
Build # 4344

Re: Fresh water expansion tank failure

Reply #2 –
The tank when working keeps your pump from having to cycle as much. 

My 2014 do no even have one now. Have not missed it  but the pump I have now is variable speed
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Fresh water expansion tank failure

Reply #3 –
They make a number of plastic pressure tanks - no rust - if you wish to replace your old tank.

Amazon.com : rv water accumulator tank

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Fresh water expansion tank failure

Reply #4 –
The rusty water wouldn't get into your system as the rusty water would just stay inside the tank.
If you like the way it's been operating you can just take it out and plug it off as it probably hasn't
worked for quite awhile.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport