cleaning fresh water tank

[Charles Skinner]

Please review me on how to "clean out" your fresh water tank and make it safe. How much bleach for a 50 gallon tank? Do you run it through the hot water heater, or do you close off the hot water tank? C. S.

[Yarome]

You'll want to run it through your water heater as well. You'll need just under 1 cup of bleach for 50 gallons (1/4 cup/15 gallons). Your FW tank might hold 50 gallons, but don't forget the couple gallons in your pipes and whatever size water heater you have. That's in addition to your tanks capacity. Don't forget to run your outdoor faucet or other fixtures if so equipped... low point drains, etc.

[wildmandmc]

taking it out for a quick ride to swish the water all over inside . helps.

[Zulu]

You'll need just under 1 cup of bleach for 50 gallons (1/4 cup/15 gallons).

 

Also, the 1/4 cup per 15 gallon should sit for at least 4 hours.

 

You can double that (so 1/2 cup bleach per 15 gallon) and let it sit for just 1 hour.

[Yarome]

 

Also, the 1/4 cup per 15 gallon should sit for at least 4 hours.

 

 

Absolutely! But overnight would be better.

[Ray,IN]

The sanitization/disinfection time is usually like this: a 10% bleach solution requires 30 minutes for complete disinfection.

The rule of thumb for water piping is: if you open a faucet and smell bleach after 30 minutes of contact time, disinfection is complete. If there is not a residual level of chlorine in water, disinfection may not be complete. Organic matter lengthens disinfection time.http://ndep.nv.gov/bsdw/docs/disinfect_drinking_water.pdf

[Zulu]

The sanitization/disinfection time is usually like this: a 10% bleach solution requires 30 minutes for complete disinfection.

The rule of thumb for water piping is: if you open a faucet and smell bleach after 30 minutes of contact time, disinfection is complete. If there is not a residual level of chlorine in water, disinfection may not be complete. Organic matter lengthens disinfection time.http://ndep.nv.gov/bsdw/docs/disinfect_drinking_water.pdf

 

I don't know where you're getting these numbers from but the 1/4 cup or 1/2 cup of bleach per 15 gallons thing is part of the NFPA 1192 Standard on Recreational Vehicles which has been around since 1937.

 

BTW, this standard describes how to disinfect the water tank -- not the water itself (as in your PDF link) -- as the OP wanted.

[Ray,IN]

Zulu, here is my reference: http://oregonstate.edu/dept/larc/sites/default/files/pdf/chlorine-fact-sheet.pdf

[Zulu]

Zulu, here is my reference: http://oregonstate.edu/dept/larc/sites/default/files/pdf/chlorine-fact-sheet.pdf

 

Ok, but this still appears to apply to disinfecting solutions (i.e. water itself) and not surfaces like a water tank.

 

Here's a link to hard surface disinfectants -- notice that the "dwell time" for bleach is listed as 10 minutes, but that assumes you have already cleaned the surface. However, since there's no practical wash to pre-clean your RV's water tank, the dwell time was boosted to 4 hours (or 1 hour for a more concentrated bleach solution).

[Ray,IN]

 

Ok, but this still appears to apply to disinfecting solutions (i.e. water itself) and not surfaces like a water tank.

 

Here's a link to hard surface disinfectants -- notice that the "dwell time" for bleach is listed as 10 minutes, but that assumes you have already cleaned the surface. However, since there's no practical wash to pre-clean your RV's water tank, the dwell time was boosted to 4 hours (or 1 hour for a more concentrated bleach solution).

That pertains to school cafeterias, which as we both know is an entirely different setting. We can agree to disagree, neither way is wrong.

Back to regular programming/subject.

This link explains the usual way to sanitize an RV plumbing system, and if necessary, how to cleanse it of algae and slime prior to sanitizing. I prefer to use Sodium Dichlor for sanitizing plumbing and disinfecting drinking water from an unknown source. That said, with regular use, an RV plumbing system should not require sanitizing unless water of unknown quality is used (creek, lake, river, etc).