Sanitizing RV fresh water tank

[huntandjeep]

How often should you do it ?

[Mudman]

  I fill with bleach water every spring.  Then rinse rinse rinse and good for us.. 45 gallons and almost a half gallon.  Might be overkill?

[j_h_nimrod]

Yep, half gallon is overkill. A half cup would be more like it. Chlorine efficacy as a disinfectant is actually inverse to concentration after a certain point, the more you add does not mean it will necessarily work better. Using untreated river and lake water in past holding tanks and constant use water systems (not drinking water), we would disinfect a couple times a year.

[Mudman]

Yep, half gallon is overkill. A half cup would be more like it. Chlorine efficacy as a disinfectant is actually inverse to concentration after a certain point, the more you add does not mean it will necessarily work better. Using untreated river and lake water in past holding tanks and constant use water systems (not drinking water), we would disinfect a couple times a year.

2 cups better?

[Oh Mah]

How often should you do it ?

Usually i winterize with the fresh water antifreeze so every year i put 2 cup bleach in the tank after about 5 gallons of water then i fill it and let set for about 3 hours,then i run out all ports for about 20 min. then i drain.not enough to hurt anything when filled back up with fresh water.(the parts per million are less than city water if you are using well)At any rate you do not need to rinse.run all ports again for about 5 min. and your good.

[Timberstalker]

I've tried different brands but the smell that RV antifreeze leaves is terrible.

[Oh Mah]

yes and fuzzy bubbles lol,after bleach its all good again.

[bowNarrow]

This doesn't help with the cleaning part but I winterize with air by blowing out all the lines

[Timberstalker]

This doesn't help with the cleaning part but I winterize with air by blowing out all the lines

For sure a better route. Lesson learned.

[Oh Mah]

actually blowing the lines out does nothing for the pump or holding tank.On my motor home getting to the pump to unhook the hose is not an option (factory placed pump).

[Happy Gilmore]

I can't remember the ratio but, when I've sanitized potable reservoirs it isn't that much bleach for a million or so gallons. Something like an 1/8th a cup for 50 gallons would be my guess off the top of my head.

[Miles]

actually blowing the lines out does nothing for the pump or holding tank.On my motor home getting to the pump to unhook the hose is not an option (factory placed pump).

On some of the newer models they specify the procedure for blowing out the lines and it says nothing about having to unhook the pump.  Our 2016 Montana 5'er lists both winterizing options.  I've used the antifreeze because they have a port and you just hold the hose in the bottle while it sucks it up.  Open faucets and water valves till orange and close them up.


A couple cups of bleach is good.  Run faucets till you smell it, then let sit for 3-4 hours.

[Sumpnneedskillin]

I just did this on my 5th wheel. 

50 ppm solution, 1/4 cup for every 15 gal, so 1-3/4-ish cup for 50 gal tank. Mix bleach with 3-1/2 gal of water, add to tank.

Run cold water faucets one at a time until you smell bleach.  Do the same with hot water.  Fill your water tank.  Let sit minimum of 4 hrs. 

Drain system, refill, flush water lines, drain tank. 

System is ready to use

[Timberstalker]

Great information here!

actually blowing the lines out does nothing for the pump or holding tank.On my motor home getting to the pump to unhook the hose is not an option (factory placed pump).

On some of the newer models they specify the procedure for blowing out the lines and it says nothing about having to unhook the pump.  Our 2016 Montana 5'er lists both winterizing options.  I've used the antifreeze because they have a port and you just hold the hose in the bottle while it sucks it up.  Open faucets and water valves till orange and close them up.


A couple cups of bleach is good.  Run faucets till you smell it, then let sit for 3-4 hours.

This is identical to mine, after reviewing it.

[Miles]

Great information here!

actually blowing the lines out does nothing for the pump or holding tank.On my motor home getting to the pump to unhook the hose is not an option (factory placed pump).

On some of the newer models they specify the procedure for blowing out the lines and it says nothing about having to unhook the pump.  Our 2016 Montana 5'er lists both winterizing options.  I've used the antifreeze because they have a port and you just hold the hose in the bottle while it sucks it up.  Open faucets and water valves till orange and close them up.


A couple cups of bleach is good.  Run faucets till you smell it, then let sit for 3-4 hours.

This is identical to mine, after reviewing it.

Make sure you drain the water heater and turn the selector to heater bypass prior to introducing the antifreeze.