Where is the Fresh Water Fill on my RV?
There are two spots on an RV that are meant for water input, the city water connection, and the fresh water fill.
The city water connection is for water hookups. A fresh water hose screws onto a brass coupler and it feeds water directly into your RV.
The fresh water fill inlet, also called a gravity fill, is for filling the freshwater tank inside or underneath your RV.
Related Product: Fill the RV fresh water tank with clean water using a Camco RV Water Filter (click to view on Amazon)
RV fresh water fill hatches can be anywhere on the outside of an RV. Sometimes they are right next to the city water connection, other times they are on the complete opposite side.
I’ve seen them on the passenger side, driver’s side, and even the rear of an RV. It’s always somewhere near the fresh water tank since it’s directly connected to it.
In this article, I’ll go over how you know when your RV fresh water fill needs replacing, how to replace it, and some tips on how to fill an RV fresh water tank.
When to Replace an RV Fresh Water Fill Hatch
Depending on the camping style an RV fresh water fill will need to be changed at different times for everyone.
If you dry camp a lot it will get a lot more wear from the freshwater hose and being exposed to the elements and sun.
It’s not uncommon for a full time RVer who fills the fresh water tank almost daily to need to change the gravity fill hatch every few years.
You can usually tell when it’s time for a replacement when the plastic starts looking worn or yellowed from the sun.
Leaks are also a big time for a replacement sign. RV fresh water fill leaks can sometimes be hard to catch because they often happen on the inside part.
Two things get connected to a fresh water fill from the inside. The hose that leads to the tank, and an air vent that leads from the top of the tank to the fill hatch.
Both of these hoses can start leaking over time and which can be a big issue since most fills are mounted to the wall above the floor.
Before you start camping you should figure out a way to see behind the fresh water fill hatch so you can check it periodically.
In our old travel trailer, the back of the hatch was accessed from behind one of the kitchen cabinets.
We had to remove the back panel of the cabinet to be able to see it.
In our motorhome, the freshwater tank was built into the dinette seats. We could see the fresh water tank and the back of the fill hatch by taking off the seat cushions and lifting the board underneath.
The motorhome had a freshwater fill leak from the previous owner. You could see the linoleum flooring curling up around the edges and there were old water stains directly underneath the back of the hatch.
We replaced the hatch and made sure the connection between the inner fresh water tank hose and the hatch was more secure.
How to Replace an RV Fresh Water Fill Hatch
Find the Right Replacement Fresh Water Fill
The first thing you need to replace an RV fresh water fill hatch is the correct part.
The most common type of fresh water fill hatch is round and white. Like this one by RecPro (click to view on Amazon).
But there are a few other kinds as well.
If your RV and city water connection are together you might need a replacement part that’s rectangular like this one by JR Products (click to view on Amazon).
There’s even a version with a door available if your RV has that style (click to view on Amazon).
Make sure you measure the RV fresh water fill currently on your RV so you get the right size.
It’s really hard to resize the mounting hole if you accidentally get something that’s too large or small.
Other Necessary Items
- Non-Leveling RV Sealant – I recommend white Geocel Pro Flex RV Sealant (click to view on Amazon).
- Butyl Tape (click to view on Amazon)
- Caulk Gun
- Robertson Screw Head Bit or Driver (click here to see more about the kinds of screws used on RVs)
- Hose Clamps (click to view on Amazon)
- Something to heat the inner hoses like a hair dryer or heat gun.
- Rubbing alcohol to clean sealant area.
Remove Connected Hoses
The water and air hoses on the back of the water fill are usually connected with barb fittings that the hoses are pushed onto.
If there are any clamps you will need to remove those first.
To get the hoses off of the barb fittings heat the part of the hose that’s connected to the fitting.
Heat will cause the hose to expand and release the barbs. It can still take a little muscle to pull a hose from a barb fitting even after heating.
Make sure you don’t heat the hose so much that it damages it.
Unscrew & Remove
Once the back hoses are removed you can unscrew the water fill hatch from the outside.
Even after the screws are removed the sealant will still hold the water fill in place. You will need to use a flat head screwdriver or scraper to pry it from the wall of the RV.
Prep the Outer RV Wall
If the old RV gravity water fill hatch was installed correctly there should be a lot of sealant left behind.
Make sure you scrape off as much of the old sealant as you can.
Clean the area where the sealant was and around it with rubbing alcohol to remove any dirt and oils that might keep the new sealant from sticking.
Butyl Tape the Back of the Water Fill
Sealing the area around the new water fill hatch is going to be the most important part.
You don’t want water to be able to get into your RV.
Put the butyl tape around the back area of the water fill hatch. Make sure all of the screw holes are covered so a seal will be created around the screw holes as well.
The butyl tape needs to make a sealed ring around the back mounting area, don’t leave any gaps or holes.
Mount the New RV Fresh Water Fill
Once the butyl tape is placed you can mount the new part to the outer wall of your RV.
Make sure the screw holes line up with the old ones.
If they don’t line up it’s not the end of the world so long as the butyl tape covers and seals the old holes.
Secure the new RV fresh water fill with the screws from the old one.
Attach the Water & Air Hoses
When you re-attach the hoses onto the new water fill you might need to reheat them again so they can slip over the barb fittings.
The hoses might be a little looser than they were before so I recommend also hose clamps to keep the hoses in place.
Make sure you don’t put the clamps on so tightly that they crack the plastic fittings on the fresh water fill hatch.
Seal Around the Outside of the Hatch
Even though there’s butyl tape helping to keep any water from getting in from the sides of the fill spout you should also caulk around the outside edges.
I recommend using an RV sealant that can adhere to metal and plastic. You also want something that’s waterproof and vibration resistant.
To be extra thorough you can cover the heads of the screws with sealant as well.
Using an RV Fresh Water Gravity Fill
Watch It While Filling
There should be a little sticker next to the fresh water fill on every RV that warns about not leaving the water hose unattended when you are filling the fresh water tank.
The tank is below the fresh water fill so gravity can be used to get the water down to the tank.
If you insert a hose and leave it running it could easily overfill the fresh water tank so much that it cracks or breaks a fitting.
The only way for water to get out of the freshwater tank when it’s being filled is through the tiny air vent, and that’s not enough to keep it from getting damaged.
Keep the Cap On When Not Filling
Since the fresh water tank in an RV is used for everything you always want to use clean potable drinking water.
Even if you don’t drink the water from your RV freshwater tank it’s used for things like cooking, washing dishes, and brushing your teeth.
Always keep the cap on so no bugs or dirt can get into the RV fresh water tank.
Use a Gravity Water Fill Adapter
The opening to an RV fresh water fill isn’t big enough to fit a standard fresh water hose fitting into.
If you can fit the hose into the opening it’s usually a tight fit that will damage the opening over time and put pressure on the entire part.
A gravity water fill adapter is a plastic pipe that’s connected to a female garden hose fitting.
The plastic pipe goes into the fresh water fill inlet.
You can attach your RV fresh water hose to it. The plastic pipe is long enough to hold the hose in place and it spreads out the weight of the hose so it’s not being put on the opening.
This version by Camco also comes with a little clip that holds the adapter in place near the opening of the water fill.
It helps spread out the weight of the hose even more and holds everything in place.
See Also: Best RV Water Hose For Drinking Water
Don’t Fill It Too Fast
Of course, you want to get that fresh water tank filled as fast as possible so you can get on the road or get out of the way of other campers if you’re filling up at a campground or RV dump station.
But blasting a ton of water into the tank is not only putting the tank at risk of overfilling, but it also puts a lot of strain on the inner hose and fittings.
Things in RVs aren’t always made with the highest quality of parts and the RV fresh water gravity fill isn’t made for high water pressures.
It’s better to take it easy and fill the tank at a medium speed so you don’t get any leaks in the future.
Have any questions about the RV fresh water fill hatch? Leave a comment below.