Understanding and Using RV Water Systems

Understanding and Using RV Water Systems

The water system in your RV provides your fresh water and removes used water from the inside of your unit. Keeping an eye on every aspect of your water system before, during and after your road trip will reduce the chances of your unit having issues. This includes taking the time to properly winterize your unit before storing it away during colder months.

Every RV has a clean and waste water system. The clean system provides potable water and the other holds waste water, also referred to as black and gray water.

Here are some tips to help maintain the fresh water system:

Hoses: Do not use a simple garden hose to connect to a water source. Purchase a hose that is designed for drinking water. Drinking water hoses are usually white, and are lead free, bpa free and have no plastic or rubbery taste. When not in use, coil up the drinking water hose and connect the two ends together. Store in a clean compartment, not with the sewage hoses.

Filters: Connect a high-quality filter to the end of the drinking hose where it connects to the outside water sources. This will purify the incoming water, removing dangerous bacteria and other contaminants.

Sanitation: Over time water can get stale and tanks can get a bit of an odor. Take time to regularly clean and sanitize the fresh water tank. Use one cup of bleach for every fifteen gallons of water the tank is capable of holding. Add bleach and fill tank with water. Turn on the water pump and open up all faucets until you start to smell bleach coming out of the faucet. Then drain the system and run water through all faucets again until the smell of bleach is entirely gone

Winterizing: When putting your RV away for the winter months you will want to properly winterize the entire water system. This includes draining the system of all water and by blowing out the lines or adding anti-freeze. Open up all water lines until you see antifreeze coming out of faucets. Don’t forget about the water heater. Drain the heater and if applicable, close the water heater bypass valve otherwise you’ll need to add an additional 6-10 gallons of antifreeze!

When draining the water system to either sanitize or winterize, do not open the water heater drain plug when the water is hot. You will want to turn off the water heater and allow it to cool before opening up.

Here are some tips for your black and gray water tanks:

Gray water: Gray water is the water that comes from sinks and the shower. The gray valve can be identified by the smaller pipe, usually 1.5” in diameter. Dump the gray water last to help clean up the hose.

Black water: The black water tank is the one that holds the water from the toilet. This tank should not be dumped anywhere but an approved RV dump site. Keep the valve to the black water tank closed at all times, even when hooked up at a campsite. This will prevent solids from getting left behind in the tank and allow time for them to break up before dumping. It also prevents odor from the sewage system from coming up into the coach.

The biggest tip about your water system anyone can give you is to make sure you are aware of the different tanks, what they are used for, and how to drain the holding tanks properly. This will help you efficiently use your water system and keep everything clean and sanitized.

Pre-Trip Checklist

Share tips, start a discussion or ask one of our experts or other students a question.

Make a comment:
500 characters remaining

181 Responses to “Understanding and Using RV Water Systems”


    When I hook up the city water to the fitting on the back of the trailer it seems to be also filling up the potable water holding tank. Is there a check valve that may have failed?

  2. Lacy Davis

    My grey water tank shows 2/3 full but nothing empties when i open the valve. Help?

  3. Gary Russell

    How do I get to the water tank to replace the fresh water hose? Thanks!

  4. Scott Lesher

    Can not find drain for fresh water tank


    Where can you purchase longer stabilizer links for the ford f53 chassis? Thank you, Les

  6. martin

    need hot water for my rig how do you start up water heater

  7. John Flanagan

    After clearing out all the winterized water and switching the bypass valve I hear the hot water tank fill, and then I am getting a lot of air coming from the outlets in the kitchen and bath room fixtures, also I am not getting hot water???

  8. Homer and Janet Helman

    Am dewinterising. Cannot get water in kitchen sink. Am I missing a shutoff valve?

  9. Ann

    water leaking on carper in rear bunkhouse above water heater and fresh water tank. lines froze and when pump is on is when it gets wet. do you know where access point to see if break in line? or could it be the wate heater or tank water outer area got so frozen that cracked somewhere at a fitting or in the line?

  10. Lee Nichols

    We have a water leak that is showing up on the carpet of the left side slider. I have tried to locate where the leak is, however I'm finding everything around the area is dry. The water on the carpet is right to the side of the refrigerator. The pantry and drawer underneath the refrigerator is also dry. Any ideas where the leak might be?