What to add to freshen up water tank..

[Ian_Edwards]

I've been using the USA's recommended procedure for sanitising the water in RV tanks for many years now.

It's one of the first things I do at the beginning of each season.

I use standard Super Market own label thin bleach, normally less than £1 for a 2L bottle.

It seems to keep all the fresh water pipes clean and clear of any of the black stuff which can grow on the insides of the pipes.

These are the instruction:


The RV code (ANSI A119.2 section 10.8) has a standard procedure that is oft quoted and works very well. We’ve added a few details, but the bones of it come straight from the code and have been reviewed and accepted by the US Public Health Service.
1. Turn off the hot water heater until finished.
2. Remove any carbon canisters or micron rated filters. Remove any faucet aerator screens. Wire mesh pump protection strainers should stay in place. The plumbing will very likely slough off a layer of bacteria during later flushing steps.
3. Clean and remove the vent screen and flush the vent hose.
4. Use the following methods to determine the amount of common household bleach needed to sanitize the tank.
1. A) Multiply “gallons of tank capacity” by 0.13; the result is the ounces of bleach needed to sanitize
the tank. This is 1/8 cup of plain bleach (no fragrance) per 10 gallons.
1. B) Multiply “Liters of tank capacity” by 1.0; the result is the milliliters of bleach needed to sanitize the
tank.
5. Mix the proper amount of bleach within a 1-gallon container of water. This will provide better mixing and reduce spot corrosion of aluminum tanks.
6. Pour the solution (water/bleach) into the tank and fill the tank with potable water.
7. Allow some solution to escape though the vent, if safe and applicable (some boats use the vent as an over flow, while in some cases the vent is in the interior). This will sanitize the vent line.
8. Open ALL faucets (hot and cold) allowing the water to run until all air is purged and the distinct odor of chlorine is detected. Leave the pressure pump on.
9. The standard solution must have four (4) hours of contact time to disinfect completely. Doubling the solution concentration allows for contact time of one (1) hour.
10. When the contact time is completed, drain the tank. Refill with potable water and purge the plumbing of all sanitizing solution. Repeat until bleach is no longer detectable.
11. If the smell of bleach persists after two refill and drain cycles, add a teaspoon of hydrogen peroxide per 20 gallons and mix. The peroxide will oxidize the hypochlorite to chloride (salt) and oxygen, neutralizing the bleach. Any excess peroxide will be harmless to drink and will have no taste. Peroxides are common ingredients in commercially available water freshening preparations. Others suggest vinegar, but vinegar at long dilutions can ferment, undoing all of your hard work.
12. Replace all filters and the vent screen.

 

[Dougy]

I've been using the USA's recommended procedure for sanitising the water in RV tanks for many years now.

It's one of the first things I do at the beginning of each season.

I use standard Super Market own label thin bleach, normally less than £1 for a 2L bottle.

It seems to keep all the fresh water pipes clean and clear of any of the black stuff which can grow on the insides of the pipes.

These are the instruction:


The RV code (ANSI A119.2 section 10.8) has a standard procedure that is oft quoted and works very well. We’ve added a few details, but the bones of it come straight from the code and have been reviewed and accepted by the US Public Health Service.
1. Turn off the hot water heater until finished.
2. Remove any carbon canisters or micron rated filters. Remove any faucet aerator screens. Wire mesh pump protection strainers should stay in place. The plumbing will very likely slough off a layer of bacteria during later flushing steps.
3. Clean and remove the vent screen and flush the vent hose.
4. Use the following methods to determine the amount of common household bleach needed to sanitize the tank.
1. A) Multiply “gallons of tank capacity” by 0.13; the result is the ounces of bleach needed to sanitize
the tank. This is 1/8 cup of plain bleach (no fragrance) per 10 gallons.
1. B) Multiply “Liters of tank capacity” by 1.0; the result is the milliliters of bleach needed to sanitize the
tank.
5. Mix the proper amount of bleach within a 1-gallon container of water. This will provide better mixing and reduce spot corrosion of aluminum tanks.
6. Pour the solution (water/bleach) into the tank and fill the tank with potable water.
7. Allow some solution to escape though the vent, if safe and applicable (some boats use the vent as an over flow, while in some cases the vent is in the interior). This will sanitize the vent line.
8. Open ALL faucets (hot and cold) allowing the water to run until all air is purged and the distinct odor of chlorine is detected. Leave the pressure pump on.
9. The standard solution must have four (4) hours of contact time to disinfect completely. Doubling the solution concentration allows for contact time of one (1) hour.
10. When the contact time is completed, drain the tank. Refill with potable water and purge the plumbing of all sanitizing solution. Repeat until bleach is no longer detectable.
11. If the smell of bleach persists after two refill and drain cycles, add a teaspoon of hydrogen peroxide per 20 gallons and mix. The peroxide will oxidize the hypochlorite to chloride (salt) and oxygen, neutralizing the bleach. Any excess peroxide will be harmless to drink and will have no taste. Peroxides are common ingredients in commercially available water freshening preparations. Others suggest vinegar, but vinegar at long dilutions can ferment, undoing all of your hard work.
12. Replace all filters and the vent screen.

Many many thanks for detailed procedure Ian. Sounds like bleach is the way to go. Very helpful.

 

[Momac]

I have the domestic water drained off for the winter.
In the spring - mid to late March I will add a litre of sterilising fluid to my 250 litre tank then fill with fresh water and pump the mixture into all pipes by opening the taps. The sterilising fluid costs £1 (or less).
http://www.poundland.co.uk/dr-johnsons-sterilising-fluid-1-litre
The mixture is left to stand in the system for a couple of hours and then pumped out using all taps . Half refill the tank and pump out to flush. Then refill again with fresh water .Usually that does the job but further flushing may be required.

Not sure I did this last year so this is reminder to self to do it this spring. Some will say its a needles precaution but costs little.

 

[Dougy]

I have the domestic water drained off for the winter.
In the spring - mid to late March I will add a litre of sterilising fluid to my 250 litre tank then fill with fresh water and pump the mixture into all pipes by opening the taps. The sterilising fluid costs £1 (or less).
http://www.poundland.co.uk/dr-johnsons-sterilising-fluid-1-litre
The mixture is left to stand in the system for a couple of hours and then pumped out using all taps . Half refill the tank and pump out to flush. Then refill again with fresh water .Usually that does the job but further flushing may be required.

Not sure I did this last year so this is reminder to self to do it this spring. Some will say its a needles precaution but costs little.

Well £1 sounds within my budget. I think I'll go with sterilising fluid first and if that doesn't work progress of o bleach...thanks all.. as usual numerous great suggestions...

 

[ex-Gladys]

I use Puriclean powder when I need to, which isn't very often.



I find that I need to rinse out the tank at least three times before refilling, otherwise the water makes my lips go numb.

Deffo +1, I mix it in hot water at home and take water cans to the boat filled with it. It mixes much better that way

 

[maby]

We spent the best part of a year on our first boat, making tea and generally drinking water from the tank before I checked and realised just how disgusting the inside of that tank was! Now, I add Puritabs with every refill and I've never seen any hint of gunge. Give it a really good wash through with Puriclean and then keep it clean with the tablets.

I did use Milton for a while - it certainly works, but the flavour is rather noticeable. Puritabs used according to the instructions have very little flavour.

 

[RobbieW]

Potable bleach at around 10ml into 200l has worked for the last few years around the Med to keep water fresh. The water turns over frequently and the bleach was available from Mercadona in Spain (other supermarkets are available ) Cant remember what the magic words on the bottle are but it is a specific product that doesnt flavour the water.

 

[smithy]

I used to get a TCP taste in the water after sterilising, I had to put a filter in to get rid of it. I read somewhere it was harmless and was caused by a reaction between the plastic pipes and chlorine. Anyone else had it?