Question:: I have a 1995 Four Winds 5000 Class A gas 30 foot long motorhome. How do I flush the water supply?
Answer: Here is a list of procedures for each type of holding tank you would want to flush, as well as some best practices.
Keep all dump valves closed until ready to dump. Leaving valves open only allows solids to dry like concrete at the bottom and sides of your holding tanks.
Don’t dump unless the tank is at least 1/2 full. If you need to dump because you are leaving but do not have at least a 1/2 tank then fill the tank until it is at least 1/2 full.
Buy a clear fitting for the dump valve or the end of the dump hose so you can see what is flowing down the dump hose and see when the waste water looks clear.
Dump the black water tank first, then the grey water tank. This will ensure that the dump hose will be left as clean as can be expected without any black water residue.
Do not use your fresh water hose to flush your waste tanks unless you want to never use it for fresh water again.
Use disposable gloves to handle your dump hose, and immediately through them into the garbage when you are finished with handling the dump hose. Don’t try to save money by keeping them for use on another day.
Black water tank or sewage:
This holding tank receives all the water from the commodes. The best way to flush such a tank is to use a built in flushing system. Just connect a garden hose to the flush outlet to your black water tank, turn on your water and open the waste valve. The recommended procedure is to keep waste valves shut until ready to dump. Also, dump only when the tank is at least 1/2 full. This will insure that the solids have enough water pressure behind them to be flushed from the tank. Once the valve is open you should continue to flush the system until the water runs clear. If you get a clear fitting for the end of your dump hose, you will be able to see the waste water coming out and see how things are going.
If you do not have a built in flush system: Buy a fitting for the end of your valve that allows you to attach a garden hose to it. These fittings are usually clear and one end connects to your dump valve, the other large end connects to your dump hose and the garden hose fitting attaches to a garden hose. Click on this link to see what we are attempting to describe: Camco 39072 RV Dual Flush RV Holding Tank Rinser.
This will allow you to direct water up the opening of the open waste valve and have it flush the tank. Another thing that you can buy is a long wand that allows you to attach a garden hose to on end and use it to flush the black tank by going through the commode opening. You do have to keep the commode valve open and temporarily run a garden hose through the RV (not our favorite method).
Waste water tank or grey water or tank:
This holding tank(s) receives all the water from sinks and showers. It is best to flush the grey water tank after the black water tank, so that you have the benefit of soapy water running through the dump hose. The best way to flush such a tank is if you have a built in flushing system. Just connect a garden hose to the flush outlet to your grey water tank, turn on your water and open the waste valve(s). The recommended procedure is to keep waste valves shut until ready to dump. Also, dump only when the tank is at least 1/2 full. This will insure that the solids, if any, have enough water pressure behind them to be flushed from the tank. Once the valve(s) are open you should continue to flush the system until the water runs clear.
If you do not have a built in flush system:
Use the same fitting as described above for the end of your valve that allows you to attach a garden hose to it.
Fresh water tank:
You don’t technically flush the fresh water tank or fresh water system unless you are sanitizing the fresh water system. What you actually do is drain the system, refill it then drain again until the system has been sanitized and there is no chlorine smell or taste.
Jill Miller is the founder of Your RV Lifestyle. Trading corporate America for the open road, Jill, along with her partner Jose, began their RV journey, making an unconventional start by wintering in New Jersey. A natural adventurer, she was motivated by a desire to explore the USA and beyond, embracing the varied landscapes, communities, and cultures across the country.
For Jill, the allure of RV living was not about material accumulation, but rather the pursuit of an adventurous, fulfilling lifestyle. A lover of golf, bicycling, hiking, and line dancing, she has carried her passions across the country, engaging with them in diverse settings. Jill’s commitment to the RV lifestyle came after years of careful research, numerous consultations with RV owners, and personal trials, including living in a rental RV.