The sanitation system on a motor home, travel
trailer or fifth wheel consists of the toilet which drains into the black water tank and the bath tub/shower, wash basin and
kitchen sinks which drain into the gray water tank. There are exceptions to this... sometimes the bath tub/shower will drain
into the black water tank.
Each tank has it's own valve but they usually dump
through the same sewer connection.
Gray water tank
Since only sink and bath water collects in the
gray water tank it needs less attention than the black water tank.
Most people use so much water whenever the RV is
hooked up for a few days, they find it convenient to leave the gray water tank valve open. Generally there is enough water
flow to flush the tank and keep it relatively fresh. If you will be hooked up for a longer time then once a week it's a good
idea to close the gray water valve, add holding tank chemical and allow the tank to fill. This helps flush out any buildup
of stuff from the kitchen sink and keeps the tank fresh.
It is quite possible for a gray water tank to get
very stinky unless it's flushed with chemicals periodically.
Black water tank
The black water tank needs more attention primarily
to control odor but also to keep solid waste and toilet paper from collecting and plugging the drain line and valve.
The black water drain valve should be left closed
until the tank is 2/3rds or more full. This helps avoid the solids building up right under the toilet and assists flushing
everything out. If the tank is not 2/3rds full when it is time to break camp, simply add water through toilet.
It's a good idea to close the gray water valve
the night before breaking camp. Then when it's time to unhook, drain the black water tank first then the gray-water tank thus
flushing the black-water completely through and 'rinsing' the sewer hose. The procedure works but I don't always remember
to close the valve the night before.
I use a rinse wand which attaches to my utility
hose and goes down through the toilet into the black water tank. It really works fast at flushing and rinsing the tank. With
all the fresh water going into the tank eventually the sewer hose is flushed clean also.
I don't rinse the black water tank every time I
dump but an occasional rinse does help control odor especially during the hot summer months.
Please don't take the time to flush your holding tanks when there
are people behind you waiting for their turn at the dump station. Flush your tank when you are at a campsite with hookups
or if you're sure no one will be needing the dump station.
After the black water tank is drained and flushed
close the valve and add enough water to cover the bottom of the tank and then add the tank chemical.
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