Mod #70: Drinking Water Filter

Mod #70: Drinking Water Filter

Submitted on: 02/14/09

     Category: plumbing
Mod Rating: 12345

(19 ratings)

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Mod Description:

The drinking water filter mod is one of those things that should come straight from the factory for all RVs. The way RV holding tanks and plumbing systems are designed and utilized tends to promote bacterial growth if not sanitized on a regular basis. And more importantly, it’s not all that uncommon to get a bad batch of water from a seemingly safe water source. In addition to sanitizing your RVs plumbing system frequently, filtering the water before it get’s in to your system goes a long way in preventing bad water taste and potentially harmful parasites and bacteria from having their way with your system. The last thing you need when camping is to be enjoying your toilet more than the outdoors.

Mod Difficulty:

Although there are several approaches to providing clean water for your RVing needs, this mod focuses on drinking and cooking water filtration. Of course, filtering your entire RV water supply system is an option but it is not always necessary. Most water sources are chlorinated and have enough protection to minimize bacterial growth. It just might not taste very good. Again, sanitizing often and not letting your water pipes, water heater, and fresh water tank sit without use will stave off 99% of bacterial growth. Assuming you have decent water to start with, the drinking water filter will provide great taste and protection in a simple to use manner.

The simplest approach to modding your RV with a drinking water filter is the countertop style filter. This system uses a standard, replaceable 10-inch filter cartridge and houses it in a plastic canister that sits on your counter. The water is fed to the unit through a tube hooked up to your sink faucet, and includes a spigot to serve the filtered water. This has the advantage of being portable. You can take the filter system with you for use in another RV, or even your home for that matter. If you are looking for a quick and easy way to get great tasting water, then your mod work here is done.

The most arguably popular drinking water filter mod though is the permanent-mount under-sink type, where the filter cartridge is mounted under the sink and the dispenser is mounted to the countertop or sink. The water supply to the dispenser is connected via a tee fitting placed in the cold water supply pipe used by the sink faucet. This makes using the dispenser easier and requires less counter space. And the filter housing is placed in an out of the way location under the sink, in a cabinet, or other convenient spot.

Doing this mod is pretty straightforward, but requires a few tools you might not have handy in your mod tool set. These are a PEX or plastic tubing cutter, and a hole saw. Using a tubing cutter will help ensure there are no burrs on the tubing after cutting, which reduces the chance of a leak at the fittings where the tubing slides in. The hole saw is necessary since the dispenser is secured by a threaded shaft on the bottom of the dispenser, which must go through the sink or countertop, and is secured underneath the sink or countertop using a large washer and nut. Some dispensers only require a 1/2″ hole for the threaded shaft so you might not need a hole saw. A 1/2″ drill bit will work. Others may need a larger mounting hole so a hole saw is a must.

Once you have the right tools for the job, installation is easy. Start by locating where you want to mount the dispenser. If you plan to mount the dispenser through the countertop, place some masking tape over the area you will be drilling through to help prevent splintering. If you plan to mount the dispenser through a metal sink shoulder, drill slowly if using a hole saw to prevent overheating the bit. After drilling the dispenser mounting hole, place the dispenser mounting shaft through the hole and secure with the supplied hardware.

The next step is to locate a suitable place for the tee fitting in the cold water line going to the sink faucet. The tee fitting taps in to the line and provides the water supply connection for the dispenser. You can tap in to any cold water line but under the sink is the most convenient. Here is where you use your handy dandy PEX tubing cutter. Before cutting, be sure your water pump it switched off and all pressure in the line is relieved. Otherwise you’re in for a real mess. Now carefully cut a 1″ section out of the cold water line, which will require two cuts. If you have enough room to move the lines away from each other 1″, then you may not have to do the second cut.

Water filter kits usually come with all the fittings necessary for a typical installation. This mod uses a plastic tee fitting which slips in between the cut tubing and a brass shutoff valve that serves both to provide the water supply to the dispenser and to turn off the supply if you need to change the filter or winterize. Thread the brass fitting in to the tee fitting using plumbers tape around the threads to prevent leakage.

Next, the water supply tubing needs to be attached to the brass shutoff valve. Don’t worry about the length of the tubing at this point. The idea here is to secure the tubing to the fitting first since doing this requires a couple of end wrenches to secure. You might not have much room to use the wrenches in a tight compartment. The brass fitting is a compression type fitting so you need to slide the compression nut on first, then the small compression ferrel. Insert the tubing in to the fitting and tighten the compression nut fairly tight but not too tight.

Now secure the plastic tee fitting to the cold water line by sliding the round plastic threaded nuts on to each side of the cut tubing, then insert the tee fitting. Secure the nuts to the fitting taking care to not over tighten. You can use pliers to do this but make sure you hold the fitting body securely so you don’t damage the water line.

The next step is to mount the water filter. Find a suitable location near the the tee fitting you just installed. The mod shown in the pictures uses a simple plastic bracket that the filter snaps in to. Secure the bracket and snap the filter in to place. Now you can measure how much tubing you need to go from the dispenser to the filter, and from the filter to the shutoff valve. Measure the distance for each and then add 6″. This extra tubing will help with any bends required when routing the tubing. Cut the tubing with the tubing cutter to the appropriate length.

Attaching the tubing is incredibly simple with the type of filter and dispenser used in this mod. All you have to do is insert the tubing in to the ends of the filter and in to the bottom of the dispenser. No compression fittings or special tools are required. The tubing may appear to be loose in the filter and dispenser but try pulling the tubing out. You can’t. The fittings hold the tubing in place and water pressure actually prevents the connections from leaking. Just be sure to connect the lines correctly, observing the filter input and output arrows.

All that is left is to do now is turn on the water pump and check for leaks. Tighten fittings if necessary but don’t overtighten. Let the dispenser run for a minute or two to eliminate charcoal sediment in the new filter. Now enjoy a great tasting glass of water!

TipWhatever brand filter you choose to buy, be sure it has been certified by the National Sanitation Foundation, or NSF. The NSF tests water filters to make sure that the manufacturer labels are telling the truth about performance. Avoid “generic” filters that have little or no information on the filter housing or packaging. Also avoid buying solely on price. Cheaper doesn’t always mean good. Remember the Yugo?
TipAlthough the drinking water filter in this mod is suitable for drinking and cooking needs, it does nothing for the rest of the water in the system. If you are not one to sanitize your plumbing system often, you should probably use a whole house filter to minimize bacterial growth and ensure safe water for other uses. See the resources below for filters designed for applications like this.

ModMyRV recommends these parts for this mod:
Culligan RV-EZ-4 RV Drinking Water Filtration System

Hole Saws and Tubing Cutters
16 Piece Hole Saw Kit with Storage Case

General Reference

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10 Comments For This Mod

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  1. reverse osmosis

    Thanks for sharing this description and i love it.

  2. cccale

    Our coach came with a water filter. I don’t know about you, but our water still isn’t right. We just bring 2.5 gal jugs. I guess we should clean the water tank.

  3. ModMyRV

    What type of water filter does your coach have? Was the coach new or used? Have you looked at the inside of the filter to see if it needs replacement?

  4. cccale

    It looks like the shurflo. The coach was used. I’m sure it’s never been replaced based on how the rest of the coach was maintained. I guess i should just put in a new filter. :)

  5. Bob Vaughn

    My wife can smell the water that has come thru a standard water hose….I have to keep a white rv hose and a carbon water filter hooked to the rv when we camp….she does not like to shower in water that has come thru a green garden hose…she thinks she smells like rubber hose when she does…..I guess my smeller is not as sensitive as hers…..

  6. Bob Vaughn

    Here is how I connect my water filter to my TT….

  7. JKleinsmith - BIKERK9

    A few things not discussed regarding water filters that I would like more discussion and information on:
    Pro & Cons:
    (a) of filtering all water placed in RV holding tanks. (stale, algie, bacteria, scum residue in holding tank?)
    (b) of leaving water in/draining filters for storage and re-use later in regards to bacteria.
    (c) of refrigerating and or freezing water filters after use for storage in killing bacteria. (Does it work/is it necessary)
    (d) Will bleach sanitize, kill bacteria on/in a filter that was previously used?

  8. Matthew Scott

    To those of you who are using standard garden hose to feed water to your RV- this is not a good idea. Read the label on a garden hose at the store- they all say “Not safe for drinking water”. They will affect the flavor of the water and may cause flu-like symptoms. Anyone that sells RV supplies sells proper hoses. You can also get brass hose ends and reinforced vinyl hose and make your own if you are handy. Commercial reinforced vinyl has a higher pressure rating and is generally more durable (and safe to use).
    And regarding filters, Aquasana has a new inline filter suitable for RV’s (under counter), with quick connect fittings (for 1/4 OD hose). The flow rate is slow, but the output quality is excellent. Don’t forget to change your filters at the recommended intervals!

  9. Denise in Ark

    The taste from the water hoses was something that I could not get around…even with “no-taste” hoses. We bought pex hose and attached male and female hose ends to it. I figured it would work because the water from the refrigerator at home isn’t a problem. It works like a charm.

    One thing about water filters that people should be aware of is that the contaminates they filter are usually limited to particulates and bacteria. In agricultural or other areas where the ground water could possibly be contaminated with chemicals, water filters aren’t going to make any difference. Knowledge is power. Know your water supply, especially if you are spending very much time in one place.

  10. Ryanallie1

    Hi All.

    Yes, a good Drining Water Hose is really important also. We have a Water System at the Kitchen sink. We also use a whole house Filter System as well. Myself, I don’t mind drining water form our Fresh Water tank, as I maintain it ver well. But the DW will only drink bottled water, go figure.

2 Trackbacks For This Post

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