Keeping the water fresh in a motorhome water tank can be difficult. When we first got the motorhome I was a bit paranoid about the water system. The previous owner never used the tank for drinking from and always carried drinking water separately. This was not really an option for us as I did not want to carry extra water due to both space and the weight. Water is a heavy load to carry. Keeping control of one water source, for me, is way more simple.
The best way to keep water potable in the motorhome is to clean the tank with an appropriate tank cleaner and flush that through the whole system at least once a year. Whenever the motorhome is not being used, drain down the tanks as a matter of course to prevent the water from going stagnant.
This blog has been written for anyone who will be using their motorhome water tank for drinking water. Even though it’s quite rare for us to drink straight from the water tank I still like to know that I can. This is my experience of the water system so far and what I have found to be effective for us. If you are not drinking from the motorhome tank and only using bottled water you can be a lot more relaxed about things but personally, I would still want my water system to be as clean as possible.
On the whole, though, we have found that we actually use the motorhome differently from how we first thought we would use it.
Make Sure Your Water System is in Good Order.
Thoroughly inspect your water system. You want to follow every pipe to and from the water tank.
As the previous owner of our motorhome was not using the built-in tanks for drinking water I was a bit suspicious about the cleanliness of the system. I took quite a while inspecting all the water pipes, cleaning and replacing where necessary. Many of the pipes had a black goo on the inside which did not look very nice to be drinking from. I am not a big fan of black bits in the drinking water.
Fortunately, most of the pipework in our motorhome was semi-clear, not completely transparent but clear enough to see if there was any discolouration. If there was I would remove these parts and sterilize or even better replace them.
After a good inspection most of the pipework was in good shape and for peace of mind, I managed to use a long pipe cleaner to remove any debris or growth in the pipes which worked really well.
Our motorhome is almost 30 years old so I was expecting a lot of cleaning up but it really wasn’t too bad. Don’t get me wrong I would not have been drinking from the system until it was cleaned but after cleaning it works great
The water tank was also a bit slimy inside. This is not really a good sign either. Also, the clips connecting the pumps to the pipes were not made of stainless steel and had rusted really badly staining the bottom of the tank.
Changing everything in the tank to stainless and giving the tank a good scrub took care of all that. Once we had finished the tank looked nice and new again and the pipework was gleaming.
Cleaning the Motorhome Water System
To clean the system we used pan brushes and pipe cleaners, lots of microfiber cloths and plenty of warm soapy water. Ours was particularly bad, most of the time cleaning with a clean cloth and water is sufficient.
Do not use any harsh chemicals and use the mildest soap you can find (we used an eco dish soap) – remember whatever you use in your system you will be consuming small amounts of. Whether you drink the water or just use it for brushing your teeth you will be consuming your cleaner of choice.
Pipe cleaners were used for the pipes – these work well to a point. Usually, you will not get then through a join so you will have to disconnect the pipe at the joins to thoroughly clean. The joins can be cleaned with the smaller pipe cleaners with a bit of warm soapy water. Generally, I was happy with the pipe cleaner we used, It really does make a difference and saves you ripping out the whole water pipe system.
We cleaned the tank out with brushes, soap and a lot of elbow grease. The tank was a bit manky looking but came back good as new. There are a couple of rust stains in the bottom of the tank caused by using non-stainless steel clips – that looks a bit unsightly but they are clean.
Flush out the Water system
We then flushed the system four or five times, we were not sure what had been going on with the water system before we purchased the motorhome. This entails filling the tanks both the hot water and cold water tanks, running plenty of water through the taps both hot and cold and then emptying all the tanks. This takes a lot of water so make sure you are near a drain or you will flood your drive. Ours was a bit dirty so we flushed a few times until we were satisfied that the water was clean.
Once the water is perfectly clean we then put in a chemical cleaner.
Using chemicals in the drinking water system
It is very important to choose what you clean the water system very carefully. A lot of people use Milton to clean their water systems. This will get the system sterilized but is very harsh on the pipes and fittings and can damage the hot water tank. I am not sure how this would affect modern water systems but it’s best to check first. A replacement hot water tank is not cheap.
In the Hymer manual, they recommend that lemon juice or vinegar is used in a very weak solution. As we had no idea of the history of care we chose to use a product called Puriclean.
This is suitable for most water systems and is gentle on the parts and the hot water tank. It is simply put into the tank.
The instructions specify that you dissolve the correct amount of Puriclean in a plastic container and add the solution to the tank. Fill the tank and run the water through the taps and the shower. This will get the solution through the system. Once you are sure that the solution has reached the taps switch them off and leave the Puriclean in the system for 1 to 12 hours.
After the time has elapsed run the water out the taps and fill with fresh – we did this a couple of times to make sure the Puriclean was out of the water system.
Once you have done this you should be safe to drink from the water system.
General Maintenance of the Water System
Water is quite difficult to store for any length of time. If you are not careful the water in your tanks can go stagnant or you start to get growth in the tank or the water pipes. As the temperature increases so does the rate of bacterial growth so it’s always worth keeping an eye on what is going on with the tanks and pipes.
A few simple precautions can prevent growth.
The trick is not to let the water lie. If you are going away on short trips just drain down the system whenever you are not using the motorhome. I leave the lid off so the tank can dry out if I am leaving it for any length of time.
On longer trips try and let the water run down as much as you can before filling. That way you keep the water in the tank as fresh as possible. Occasionally drain down the tank before filling back up.
If the temperature is high you have to be very vigilant and check the tank for any growth. If you are getting growth I would try putting some lemon juice or vinegar in the tank, they are antibacterial and won’t kill you – unless you are allergic to citrus! Flush this through the taps, shower as you normally would and then put in fresh water.
Generally – now that we have thoroughly cleaned the water system with Puriclean, a flush through with vinegar or lemon juice every 6 months seems to be working for us.
How to Sterilise the Water Tank
If your tank is very dirty and had been neglected and you feel that Puriclean or lemon juice just won’t cut it then many people have used Bleach. Now, we used Puriclean and a lot of scrubbing to get the water system clean enough for us to use and we have had no problems. Our tank was far from what you would call clean.
If you want to go down the bleach route you have to be aware that it will have an effect on stainless steel – our hot water boiler is made from stainless. So be aware.
I would put one or two cups of bleach, max with the 100 litres we have. Pull it through the taps shower and toilet. Let it sit for no more than one hour.
Empty the tank and fill with fresh a couple of times and then pull the fresh water through the taps until there is no more bleach smell or taste.
This will give peace of mind and a sterilised water system. Just remember the risks and make sure you flush out all the bleach.
It’s also worth mentioning that you should be very careful where you drain you bleachy tanks – not much will survive a dousing in bleach.
For me, it’s the environmental factors that put me off using this method and I am not a big fan of drinking bleach.
Cleaning the waste water tank
Once you have used the water in the fresh water tank it all goes into the grey water tank or waste tank. Looking after the waste tank is important. In the summer the waste tank can quickly get whiffy so there will be all sorts of things growing in there.
What is the best way to look after the waste tank?
I look after the grey water tank in the same way we look after the water system. When you are running the water through the taps that will go into the grey tank and take care of what is growing in there.
A lot of people like to put bleach down the motorhome drains but I wouldn’t do that. If I was having problems with the grey tank I would pour some vinegar down the drain which will take care of most problems. Half a bottle should be enough down the sink and flush through with the tap to get rid of the vinegar smell. Let it sit for a while or even better go for a drive and your grey tank should be smelling much better – vinegar is much nicer than stagnant dishwater, usually.
Our Grey water tank is hard to reach and is underslung so difficult to get to. There is a hatch on it but as yet I have not been brave enough to take that hatch off and clean it out – maybe another time but at the moment it is working perfectly so I will save that job for a later date.
Hope this helps with your water cleaning choices and decisions.
All the products we used on our water system can be seen on the Water System page
Good luck with the cleaning.