Cleaning and sanitizing cistern tanks isn't as hard as it may seem. The whole process can be done with minimal time and cost. Take a look at the steps below to help you get the best result from your cleaning attempts.
Step 1 - Clean out Construction Dirt or Old Water
If you just had the cistern installed, you may have left over residue from construction. Get rid of that excess dirt with a simple broom or wet cloth. If it is an old cistern, be sure to drain out all the water before you get in there.
Step 2 - Bleach the Walls of the Cistern
The walls of the cistern should be scrubbed down with a bleach mix to ensure the safety of the cleaning process. Mix 1/4 cup of bleach with 10 gallons of water. Use that to clean the walls, but make sure that there is an air hole available for ventilation. You do not want to cause any damage with bleach fumes trapped inside of the cistern tank. You can also use chlorine for this if you want to, but most people opt for bleach because it is readily accessible right at home.
Step 3 - Wash the Bleach out
Take a hose and spray down the inner areas of the cistern until you can no longer smell the bleach.
Step 4 - Clean out the Cistern Frequently
Unless an issue arises, plan to clean out your cistern at least once every five years. That will ensure that you don't have a buildup of bacteria or any other problematic elements. If something like that does come up, follow the tips below for disinfection.
Step 5 - Use a Chlorine Pump for Disinfection
This is a simple method of sanitation. Put chlorine into the water as it comes into the house. Leave it in there for five minutes, the amount of time it takes to kill the bacteria. Use a storage tank in between the point of use for the water and the point of release. Run your water for a bit to get out some of the chlorine. It may leave a funny taste.
Step 6 - Use Bleach to Sanitize
Add one ounce of bleach for every 200 gallons of water you have in your cistern. Treat with this once a week. This will not be as effective as the chlorine method, so if you can use the chlorine, do so. The taste will fade in time.
Step 7 - Replace when Necessary
If you clean your old cistern, but have a substantial amount of problems with it, consider calling in a professional to come take a look at it. Tanks that get too old lose their storage and disinfection capabilities. Don't take any unnecessary risks. Your water is only as clean as the cistern it comes out of, so regular care is vital to the safety of you and your family.