Tech Tips:
Cleaning Your Fresh Water Tank
By Bill Whitney
One of the problems we face every spring is cleaning
the fresh water tank and water lines on the boat before heading
out for summertime adventures. The goal is to kill and flush out
all of the nasty algae and bacteria that have been growing in the
fresh water system since last fall. There are several ways to
accomplish the task, and several steps in the method described
here. First you have to drain as much of the anti-freeze and old
water out of the system as you can. This includes all the water
lines, water heater (if you have one), and faucets.
After draining the system take a quarter cup of house-
hold bleach for every fifteen gallons of water that your fresh
water tank holds. Mix the bleach with water, filling a
one-gallon container and pour about one fourth of it into the
fresh water tank. Let this sit for 5-10 minutes, since most of the
‘bad actors’ are in the bottom of your tank. Then add the
remainder of the water/bleach mix and fill the fresh water tank
as full as you can with water. Turn the water pump on, open all
the faucets and run the water until you smell the bleach at each
faucet, then close the faucets and shut off the pump. If the boat
is in the water go for a sail so the water can move around to
assist in cleaning the entire tank. Let it sit for at least 12 hours.
Drain the entire system again and re-fill the fresh water tank
with potable water. Make sure you use a white non-toxic drink-
ing hose with an inline water filter to refill the system. Hoses
not labeled safe for drinking water can contribute to lead and
other dangerous chemicals getting into the water. Open all of
the faucets and run the water until you no longer smell any
bleach. It may be necessary to refill and drain your tank with
fresh water again to eliminate all signs of bleach from the
system. Once this is done it is safe to use your water system.
Got questions? Need answers? Bill is happy to respond to
FSS members’ inquiries and technical questions. Contact him at
techtips@fss.org.
