Our water tanks are fairly new. Removing the old stainless steel tank was one of the first projects we did back in 2013. That tank had at least one hole in it and the entire bottom was rusty brown. We think the old tank was about 90 gallons. The two polyethylene, rotomolded tanks we replaced it with total about 76 gallons (40 gallons and 36 gallons).
The tanks have been installed for several years, but we really only use them when we leave the dock or lose power at the marina. The majority of the time we’re connected to the dock water. The area we live in is very rural and the marina is on well water. The water is regularly tested and completely safe to drink, but it tastes like crap. It maxes out on the hardness scale as well.
Filtering the Water
We used to lug bottled water to the boat every week before we bought the Berkey filter for drinking water. It’s taken us a few years to get a good system to deal with the water, but now we think we’ve got it. Three filters and a water softener for all the water that comes into the boat. Plus the addition of the Berkey filter for drinking water. Even with all of that, our water tanks still get a little dirty.
Cleaning the Tanks
The first thing we did was drain the tanks (they were nearly empty to begin with). Then we added some Clorox bleach to each tank (multiply the tank capacity by 0.13 to get the correct ratio in ounces to sanitize). Then we filled the tanks about half full, scrubbed them with a new scrub brush, then continued filling them. We let the bleach solution sit in the tanks for about 4 hours. Before emptying the tanks overboard, we neutralized the chlorine bleach with hydrogen peroxide and used a clean, spare bilge pump to circulate the water.
Sodium hypochlorite (bleach) mixed with hydrogen peroxide (H2O2) produces salt water (NaCl and H2O), oxygen gas (02) and some heat [NaOCl + H2O2 -> NaCl + H2O + O2]
Before filling up the tanks we changed all the filters, regenerated the water softener, and added a water treatment to the tanks (Starbrite Aqua Water Treatment and Freshener). This is the first time we’ve cleaned the tanks, and I don’t think it’s something we’ll have to do often (at least I hope not).
