# Sanitizing Water Tank



## FLYakman

I need to sanitize my 40 gal fresh water tank. While we do not use the tank for drinking we do use it for cleaning etc. so I'd like to have it sanitized.

if i go by what's on the Clorox bottle I would need to add 2.5 cups of bleach for 40 gallons of fresh water. does this sound right? Sounds like a lot to me.

Need advice from those of you who have done this- which I assume is most of you. How much bleach to use?

Thanx!

FLYakman


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## GSJ

I normally use 1 cup for 40gl. throughout the whole system. Then you have to leave it for an 1 hr or so. Then fill and flush the tank 3 times, then I flush the system using the pump for about 5 minutes, then flush the whole system connected to the "city" line for about 1/2 hr with all the taps open. It seems like a long time, but I hate the taste of bleach. I've learned this through trial and error. I sanitize every year.


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## SDCampers

After I purge all the anti freeze from the lines I open the water heater bypass, put plug back in the water heater, add two cups bleach to fresh tank and circulate through the system including water heater. I let this sit for several hours, sometimes overnight. Then I empty the fresh tank and flush everything with clean water, empty again and refill with fresh the day before a trip.
We do drink the water and use it for coffee and I don't notice a bleach taste. Seems to work for me.


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## CamperAndy

FLYakman said:


> I need to sanitize my 40 gal fresh water tank. While we do not use the tank for drinking we do use it for cleaning etc. so I'd like to have it sanitized.
> 
> if i go by what's on the Clorox bottle I would need to add 2.5 cups of bleach for 40 gallons of fresh water. does this sound right? Sounds like a lot to me.
> 
> Need advice from those of you who have done this- which I assume is most of you. How much bleach to use?
> 
> Thanx!
> 
> FLYakman


That amount is more for drinking. If you are just using it for cleaning then half would be enough. Still need to let it sit and then do a couple of rinses.


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## FLYakman

OK then. 2 cups it is !

Thanx to all.

FLYakman


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## KTMRacer

bleach is a pain to get rid of, smell and taste, but it is a cheap way to go. I switched to using "Spring Fresh". costs more, but is quicker to flush out and doesn't leave the bleach odor/taste. 1 gallon treats a 100 gallon tank, so I just use 1/2 gallon each spring. Fill, purge through the lines, let it sit, then flush/drain, refill and do a final flush and ready to go.


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## FLYakman

KTMRacer said:


> bleach is a pain to get rid of, smell and taste, but it is a cheap way to go. I switched to using "Spring Fresh". costs more, but is quicker to flush out and doesn't leave the bleach odor/taste. 1 gallon treats a 100 gallon tank, so I just use 1/2 gallon each spring. Fill, purge through the lines, let it sit, then flush/drain, refill and do a final flush and ready to go.


I have not heard of "Spring Fresh" before. Like the guys in the Geico commercial, I live under a rock. Where do you get it and what's the price? Other than what you are using it for what is it used for?

FLYakman


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## Lmbevard

Did a search on Google and came across this;

From the US Navy
From Department of the Navy - Manual of Naval Preventive Medicine: 
Chapter 6: Water Supply Afloat:

Chlorine Dosage Calculator 
http://www.vnh.org/PreventiveMedicin...ter6/6.25.html

Disinfection of Potable Water Hoses and Appurtenances
http://www.vnh.org/PreventiveMedicin...ter6/6.23.html

Emergency Disinfection of Water for Drinking and Cooling Purposes
http://www.vnh.org/PreventiveMedicin...ter6/6.24.html

Required Halogen Residuals
http://www.vnh.org/PreventiveMedicin...ter6/6.26.html

Chlorine readily combines with chemicals dissolved in water, microorganisms, small animals, plant material, tastes, odors, and colors. These components "use up" chlorine and comprise the chlorine demand of the treatment system. It is important to add sufficient chlorine to the water to meet the chlorine demand and provide residual disinfection. The chlorinated water should retain a slight chlorine taste and odour.

The chlorine that does not combine with other components in the water is free (residual) chlorine, and the breakpoint is the point at which free chlorine is available for continuous disinfection. An ideal system supplies free chlorine at a concentration of 0.3-0.5 mg/l. Simple test kits, most commonly the DPD calorimetric test kit (so called because diethyl phenylene diamine produces the color reaction), are available for testing breakpoint and chlorine residual in private systems. The kit must test free chlorine, not total chlorine.

The contact (retention) time in chlorination is that period between introduction of the disinfectant and when the water is used. A long interaction between chlorine and the microorganisms results in an effective disinfection process. Contact time varies with chlorine concentration, the type of pathogens present, pH, and temperature of the water. Contact time must increase under conditions of low water temperature or high pH (alkalinity). Complete mixing of chlorine and water is necessary.

If a system does not allow adequate contact time with normal dosages of chlorine, superchlorination followed by dechlorination (chlorine removal) may be necessary.

To treat 100 Gallons of water (standard chlorination):

5.25% Sodium Hypochlorite - Household Bleach
Contact Time -vs- 5.25% Chlorine Concentration:
2 Hours - 100 ppm (about 3 Cups or 26 ounces Bleach for 100 Gallons Water)
8 Hours - 50 ppm (about 1.5 cup or 13 oz. per 100 gal.)
24 Hours 25 ppm (about 3/4 cup or 7 oz. for 100 gal.)

65% Granular Calcium Hypochlorite Powder - HTH, Perchloron, or Pittchlor
Contact Time -vs- 65% Chlorine Concentration: 
2 Hrs - 100 ppm (2 ounces per 100 gal.)
8 Hrs - 50 ppm (1 oz per 100 gal.)
24 Hrs - 25 ppm (½ oz. per 100 gal.)

Minimum Halogen Residuals:
Standard: 0.2 ppm chlorine after 30 minutes in tanks
Disinfection: 100 ppm chlorine initially, then 50 ppm after 4 hours in tanks

Superchlorination provides a chlorine residual of 10 times the recommended minimum breakpoint chlorine concentration. Retention time for superchlorination is approximately 5 minutes. Activated carbon filtration removes the high chlorine residual.

Shock chlorination, at about 4 times the recommended minimum breakpoint chlorine concentration, is recommended whenever a tank is new, repaired, or found to be contaminated. This treatment introduces high levels of chlorine to the water. Unlike superchlorination, shock chlorination is a "one time only" occurrence, and chlorine is depleted as water flows through the system; activated carbon treatment is not required. If bacteriological problems persist following shock chlorination, a continuous chlorination system should be used.

Potable water tanks, pumps, hoses, & fittings are disinfected by filling with a solution containing not less than 100 ppm FAC. The solution must be in contact with the entire internal surface of the system for not less than two minutes. Flush the system 30 to 60 seconds with potable water prior to use.

I bought some Super Shock for swimming pools that I will try before the next trip. All it should tank is a simple teaspoon full for the full tank. The nice think is that it will leave less taste since almost all liquid bleaches has other things added that gives the bad taste. Will let you know how it works.


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## Jewellfamily

I use bleach to purge my system like everyone has mentioned here for the 1st sanitizing of the year (spring clean out). I also use the water purifier that you can buy in the camping section of walmart through out the year. It is also a sodium hypoclorite (bleach) solution but for some reason doesnt seem to leave a bleach taste and the water tastes fresher. I use it at about 1/2 the dose on the bottle directions.


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## Scoutr2

I sanitize my system a couple times a year - in the spring, and also after a long spell of hot weather when we have not used the trailer for several weeks. I usually add 1/2 cup bleach to a full tank of water, pump the chlorinated water through all the lines, then let it sit for several hours. (I drain the HW tank, then let it fill back up as I sanitize the system. The water in the heater can get REALLY funky!)

After the chlorinated water has been in the system for several hours, I drain the tank, then partially fill it with fresh water and 1/2 box of baking soda, which will absorb tastes and odors and sweeten the system after the chlorine. Then I pump that thru the system and let it sit for a couple hours - drain the tank again - then add fresh water and flush the system of the baking soda (and drain the HW heater again).

It sounds like a lot of work, but really is not. I just fill, then do other things while I wait for the next step (like hoisting a few cold adult beverages!).

Also - if I know we will not be using the trailer for more than 2-3 weeks, I drain the entire system by removing the low-point drain caps, opening all faucets, and draining the HW heater. No sense letting water sit in the system and inviting unwanted bug growth! (And who knows the condition of campground water sources? Some are good - some are just untreated wells.)

Mike


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## KTMRacer

FLYakman said:


> bleach is a pain to get rid of, smell and taste, but it is a cheap way to go. I switched to using "Spring Fresh". costs more, but is quicker to flush out and doesn't leave the bleach odor/taste. 1 gallon treats a 100 gallon tank, so I just use 1/2 gallon each spring. Fill, purge through the lines, let it sit, then flush/drain, refill and do a final flush and ready to go.


I have not heard of "Spring Fresh" before. Like the guys in the Geico commercial, I live under a rock. Where do you get it and what's the price? Other than what you are using it for what is it used for?

FLYakman
[/quote]

Camping world carrys he "spring fresh" and I've seen it at other RV dealers parts and supplies department. It is about $12 for a jug big enough to treat 100 gallons. My tank is 43 gallons, so I just use 1/2 a jug. yes, it is more expensive than bleach, but it is easier since it takes less rinsing to get the water to be "normal" tasting and smell.


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## Tangooutback

I am curious to know how many of us use water tank to store drinking water? I do not use mine for drinking water at all.


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## Braggus

Tangooutback said:


> I am curious to know how many of us use water tank to store drinking water? I do not use mine for drinking water at all.


Have not used mine yet, still empty since the day I purchased the TT


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## Scoutr2

Tangooutback said:


> I am curious to know how many of us use water tank to store drinking water? I do not use mine for drinking water at all.


We do not use the tank water for "drinking water," strictly speaking. I installed an under-sink water filter (Omni Filter) that feeds a drinking water dispenser that I installed to the right of the small kitchen sink. The charcoal filter removes taste and odor. We use that water for cooking, hot chocolate, coffee, tea, Kool-aide, etc. We bring bottled water along for drinking.

Mike


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## FLYakman

CamperAndy said:


> I need to sanitize my 40 gal fresh water tank. While we do not use the tank for drinking we do use it for cleaning etc. so I'd like to have it sanitized.
> 
> if i go by what's on the Clorox bottle I would need to add 2.5 cups of bleach for 40 gallons of fresh water. does this sound right? Sounds like a lot to me.
> 
> Need advice from those of you who have done this- which I assume is most of you. How much bleach to use?
> 
> Thanx!
> 
> FLYakman


That amount is more for drinking. If you are just using it for cleaning then half would be enough. Still need to let it sit and then do a couple of rinses.
[/quote]

Thanx. I'll do this on Saturday. Leaving 6/19 for a 6 week camping trip. outer Banks of NC and then Boone NC. Got the OB all ready to go. Be back to FL in August


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## KTMRacer

Tangooutback said:


> I am curious to know how many of us use water tank to store drinking water? I do not use mine for drinking water at all.


we use ours for cooking, tea, coffee, and drinking water. water for cooking, drinking etc. goes through a culligan under the sink filter with a spout by the sink. Been doing that for years. Before we leave home, we fill the cooler with 1 litre bottles of water, but as they get used, we just refill them from the tank. I always use a charcoal filter on water going into the tank, as well as the "camco" water stuff (mild bleach).

We are seldom at a campground that has water hookups anyway, usually refill the tank from the campground water supply.


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