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9 Tips to Fill RV Fresh Water Tank in 2023

Writen by Dane Heldt

Fact checked by Robert Clark

Whenever you will be going on an RV trip, you need to have enough fresh water for all your needs during your excursion. This is the main reason why you need to know how and where to fill an RV fresh water tank before every trip.

Where to Fill RV Freshwater Tank

If you are a new RVer and you are not all that sure how to do then read this entire article on tips to fill RV fresh water tank to learn about the correct procedure.

9 Tips & Tricks to Fill RV Fresh Water Tank

Tip #1. Locating Your Freshwater Tank Connection

The first step is to find out where you will be connecting your water source. For most models of RVs, the freshwater connection is usually at the rear of the vehicle. It is either behind a master panel, or it has a screw-top lid on an inverted spout.

In newer RVs, the freshwater connection has a Y-valve that you can use to divert the city water source directly into the water tank or through the pipes. You should check your RV owner’s manual for the specifics regarding your RV’s make and model.

Tip #2. Safety First

Before you hook up your RV to your freshwater source, take a couple of minutes to go through some simple safety measures. One is that whenever you are adding water into your RV, regardless if it is from the city water port or any other source, always use equipment that is FDA-certified safe for use on freshwater.


Always use potable water. It is also strongly urged that you use an external in-line water filter. Even if your RV already has an internal water filter in its plumbing system, it is never a bad idea to have an extra layer of protection. Having an external filter will help keep debris and sediment out of your water tank.

With that, you can save a lot of money in the future. Before you add in any water, make sure that your freshwater tank is clean. Flush it out with clean water a couple of times just to be sure. If you haven’t been using your RV for a while, you should thoroughly wash the tank using soap and a bit of bleach to completely clean and disinfect the tank.

The freshwater tank can become a cesspool of bacteria if you do not disinfect it properly before you use it. The last thing that you want to happen during your RV trip is to battle a bad case of diarrhea, which does not only make you use even more freshwater but will also dehydrate you.

Furthermore, you should be confident about the cleanliness of your water source, the water tank and the hoses that you will be using. If there is any shred of doubt, follow your gut instincts and clean them beforehand and look for another water source.

Tip #3. All About Y-valves and Pressure Regulators

Y-valves and pressure regulators are highly recommended but still optional, pieces of kit that you can add to the water refilling process. These are not that expensive at all so you should seriously add them to your rig.

Having a Y-valve installed means that you can hook up the freshwater input hose and the tank cleansing hose at the same time. This allows you to turn one of them off and the other one on without having to disconnect the hoses.

On the other hand, the pressure regulator is a nice addition, especially if you will be using the water facility of your campground. The reason why you need a pressure regulator is that the plumbing in campgrounds is usually irregular.

A sudden burst of water can be enough to cause serious damage to the internal plumbing system. Just one good water hammer will dislodge your RV’s delicate plumbing system.

Tip #4. Find Alternative Sources of Water

Most public campgrounds, like National Parks, have no freshwater hookup systems. If you find that this is the case, there should at least be a simple spigot so you should look for one. You can usually find them near or in the dumping station. They could also be in the areas between campsites.


You should be able to connect your RV’s freshwater hose directly to the spigot without any additional equipment. If you are running low on water, ask the homeowners that you pass by on your route if you can hook up to their water spigot.

Of course, you should ask nicely and pay for the water that you will be getting. You need to maintain the positive image that people have of RVers.

Tip #5. Taking Your Needs into Consideration

When you are refilling your freshwater tank, it is important to take into consideration where your campsite is located. Water is heavy. At almost 10 pounds per gallon, you truly need to consider how much you will be using to prevent weighing down your RV too much.

If you will be going on an RV trip alone, or if there are two of you going on the trip, then you might not need to have a full freshwater tank. Just carry enough water for both of you and maybe a bit extra. On the other hand, if you will be taking your whole family with you, then have your freshwater tank filled up to its maximum capacity.

If you carry too much water, not only will the added weight put a lot of strain on your RV’s suspension, it can also hit your gas mileage hard. Worst of all, too much water might put you over the GVWR (Gross Vehicle Weight Rating).

This is a value that when exceeded can cause a slew of problems, like broken axles. Furthermore, it might make your insurance company refuse to cover your accidents.

Tip #6. Don’t Completely Fill Up Unless You Need To

You should only fill up your freshwater tank if you plan on traveling far and you are not sure if there will be enough water hookups on the way. For instance, if you are planning to set up camp in your local national park, you can probably fill up your tank once you get there.


On the other hand, if you will be dry camping/boondocking at a place where you are unsure if there will be any sources of freshwater nearby, consider filling up your tanks with water before you park your RV at the campsite. Also, you should take a couple of extra water containers of fresh drinking water just in case.

Tip #7. Be Conservative with Your Water Use

You should never take your water for granted. There are millions of people who do not share the benefit of having an accessible source of clean water, so you should make every drop count. Furthermore, you would not want to run out of water when you are out in the sticks.

Washing your dishes, showering, doing your laundry, flushing your toilet, all of these acts will deplete your freshwater stores quickly, so you need to be conservative when using water. For instance, use biodegradable plates, spoons, and forks so that you can lessen your dishwashing load.

Also, pack more than enough clothes. This will prevent you from having to do laundry during your trip unless it is truly necessary. Also, you should carry a couple of extra gallons in other containers like jugs, bladders, and drinking bottles.

Tip #8. How to Properly Dispose of Extra Water

When you use up all sources of freshwater, it will either go to the grey water tank or the black water tank. The grey water tank is for the water that came from the sinks and the shower drain. The greywater is dirty and has traces of soap in it.

On the other hand, the black water tank contains waste from the toilet. It is kind of like the septic tank of the RV. When emptying the tanks of the RV, it is best to empty the black water tank first and the greywater next because the soapy grey water will help clean the output hose.

Most importantly, you need to have a separate hose for disposing of wastewater and another for freshwater refilling. You should use different colored hoses to designate them from each other (most people use white for freshwater and orange for flushing) and write on them with a permanent marker to prevent them from being mixed up.

Also, store them at separate places so that the wastewater will not contaminate the freshwater hose.

Tip #9. Never Ever Drain and Drive

Some RVers have a bad habit of opening their wastewater tank and then driving home. Always empty your tanks in designated dumping stations. If you need to empty your freshwater tank, turn on the pump and direct the hose into your sink or in the toilet. The extra water will help dilute the contents of the wastewater tanks and make them easier to empty later.


When you know tips to fill an RV freshwater tank, you are now pretty much ready to go on your very first RV road trip. Also, by knowing exactly where in your RV you can hook up the city water supply and how to do it properly, you will always have more than enough water to use in your RV trips.

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