My Fifth-Wheel RV

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Sewer System

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Larger fifth-wheels and pushers have two waste holding tanks: grey water and black water. The grey water tank is used to accumulate the flow from sinks and showers, including the kitchen sink. The black water tank holds output from the toilet. Because tank space is limited, they have to be flushed periodically, and there is a recommended procedure for doing so.

Start by hooking your flexible sewer hose up to the sewer outlet on your rig, usually located at the bottom under the carriage. Then pull out the stopcock which controls the black tank first. After no more sewage flows through the flex hose, push the stopcock back in and then do the grey tank in the same manner. Doing the tanks in this order allows the grey water to cleanse residue left in the line from the black tank. After both tanks ate done, wiggle the flexible hose a bit to make sure it is clear. Then disconnect it and rinse it with fresh water.

You might want to keep a separate water hose for rinsing the sewer line. It's not a good idea to use your drinking water hose to rinse sewer lines; otherwise you might contaminate the end of the hose with excrement. You can probably use a separate hose about 2-3 feet in length.

Make sure you stand by the sewer line while it is flushing - don't walk away. Things happen, and there are few things worse than having a pool of cess around your trailer. Put a rock or something heavy on the flexible hose where it goes into the sewer. Otherwise the hose could shake loose due to vibration caused by outflow from the holding tanks.

You will undoubtedly notice people leaving their flexible hose hooked up all the time. There's nothing wrong with it, but take a little advice and leave the grey and black tank stopcock plugs pushed in, so that no flow occurs. If you leave them open it is possible that the flex hose could work its way out of the sewer collector, either from vibration or by someone kicking it loose, like careless kids playing around your rig. If you leave the flex hose attached all the time, it shouldn't be a problem for you to go out occasionally, flush the tanks, and then push the stopcocks back in.

Here's a piece of advice you probably wouldn't expect: don't dump your tanks too often. If you can, wait until they are almost full to dump. Why? The bacteria in your black water tank needs time to work.

-- more

-- tank minder
-- tablets
-- Camco SuperKit sewer hose and attachments
-- our rv - black 41 gal - gray 57 gal
-- bleach in rv black tank? - jury still out

flush with lots of water


Here is a diagram of the sewer system for our Open Range fifth-wheel. Yours is likely to be similiar.

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Use RV paper only. This is different from regular bathroom paper in that it is biodegradable and will flush through your sewer system better, thus preventing ugly stoppages in the line.

Leave a little water in the toilet while travelling. This will be useful if you need to stop on the side of the road somewhere to go to the bathroom. Also, it's better to leave waste in the toilet rather than flushing, because you may need to go again before you arrive. It may not be pleasant looking but probably better than scarring up the sides of the bowl.

-- 15-20' of sewer hose, either one long hose or one or two extensions. As mentioned in the blogs, you wouldn't believe the awkward places some campgrounds position their sewer pipes.
-- don't dump black tank too often. if too often then solids may be left behind. the fuller the tank the more solids will break down -- use tank minder
-- use pink rv antifreeze only - regular antifreeze or windshield fluid will destroy tank seals
-- shower and sinks - gray water; toiled - black water
-- brown rain gutter used for sewer hose; accordion support

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