This post contains affiliate links (I get a commission at no extra cost to you for purchases made through links in this post).
It is good to know the different ways of draining your fresh water tank in your motorhome (RV) since they have other benefits and can help keep your fresh water fresh and your grey water tank clean simultaneously!
As a general rule, you empty the fresh water tank by locating the drain plug inside it and pulling it up; the fresh water will drain out underneath your motorhome via a hose. On newer motorhomes or RVs, you have a drain valve underneath your motorhome that you turn a handle on to drain.
It can sometimes be tricky to know how you should empty your fresh water tank the best way, maybe you only turn on all the water taps and the shower to empty it, or perhaps you usually don’t do it.
The Different Ways of Draining a Motorhome Fresh Water Tank
You can locate your drain plug inside the fresh water tank or the drain valve outside the motorhome to drain the whole water tank fast; you can also open all the taps in the kitchen, bathroom, and shower to pump the water from the fresh water tank to the grey water tank.
The benefit of draining the fresh water tank the fastest way with the drain plug or valve is that you save a lot of time. If you have a dirty Water tank with algae inside, it will also be best to drain your tank this way, so you don’t have to pump this dirt further into your water system via hoses and filters.
It will also be much easier to get this dirt out from the tank since things like sand or dirt that stays on the bottom of the tank is difficult to impossible to pump up with the water pump because the hose that goes from the fresh water tank to the water pump usually don’t go all the way to the bottom of the tank.
The other way of doing it by turning on all the taps gives you the main benefit of draining your fresh water tank and filling up the grey water tank with clean water so you can give that a good rinse or clean at the same time.
As a general rule, water pumps dont like to run dry, so if you dont have experience with water pumps or know how yours work, make sure to turn it off before you are out of fresh water.
If you would only drain your fresh water tank by turning on all the taps, be aware that the water tank won’t become empty. Instead, you will have quite a lot of water left since the hose that goes to the water pump doesn’t go all the way to the bottom; as previously said, this is why I prefer combining the two forms of emptying the tank.
The Best Way to Empty Your Fresh Water Tank AND Clean Grey Tank at The Same Time
Start by emptying the grey water tank, turn on all your water taps inside the motorhome (RV), and pour some vinegar or a detergent that dissolves fat into the sinks, so it goes down to the grey water tank. Keep an eye out for the water level and turn off the taps when the fresh water tank is almost empty. Now drain the last water via the drain plug or drain valve.
Now you can drive around a bit with your motorhome so that the water inside your grey water tank has a chance to splash around and hopefully clean off some more dirt from within the grey tank and clean the level sensors inside the tank since one of the main reasons those stops working is that they get too dirty. Then empty your grey water tank.
This way, you both empty your fresh water tank and, at the same time, give your grey water tank some love to avoid odor or faulty level readings if the sensors get dirty.
Speaking of the grey water, I have also made an article and a youtube video about what grey water is and one that goes through a more in-depth way of cleaning the grey water tank and the holding tank sensors that I recommend you to read.
Should I empty the fresh water tank in Motorhome (RV)?
As a general rule, you should empty your fresh water tank in a motorhome or RV if you don’t intend to use the water within two weeks; otherwise, bacteria and algae will start growing. Or If you plan on driving a long distance and know you have a water source at the destination for better gas mileage.
If you, like me, live full-time in your motorhome or RV, you will use your fresh water within these two weeks anyway and refill more frequently than that and probably keep moving the motorhome from time to time so that the water won’t be still and require as much attention. Nor will it get the opportunity to grow bacteria or algae the same way as if you go on trips twice a month and leave the tank with water between the trips.
Are you wondering if drinking fresh water in your motorhome, RV, or caravan is safe? And how to keep it safe to drink. I suggest you read my other article where I go through this.
If you stay at campsites and know that you will have an easy way of refilling water at your destination, you do not need to drive with a full water tank. Instead, it will save you a lot of weight, give you better gas mileage, and, most importantly, increase the capability of your brakes if you drive with an empty water tank.
I recommend getting used to emptying your tanks and developing a system that works best for you, it might be a bit tricky the first time but after a while it will be part of your routine and help you keep your fresh water fresh!