Installing a Double Kitchen Faucet and Ultrapure RV Water Filter

Fri Aug 02 2019

Upgrading our kitchen faucet and adding a dedicated filtered water spout for the Ultrapure under-sink filter system.

Installing a Double Kitchen Faucet and Ultrapure RV Water Filter

For a while now, we've been considering installing a water filter, and then recently, our kitchen faucet broke - the flow rate dropping significantly. This was the impetus we needed to get on with this project. It only took a couple hours, and the end result is great!

RV Kitchen Faucet
Our original kitchen faucet has almost completely stopped working, so this was a great opportunity to replace it!

Why we want a water filter

In the last 12 months of living full-time in our RV, we've never drunk the water directly from our kitchen faucet. We'll boil it for tea and coffee, use it for cooking and washing up, but have never drunk it directly.

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Honestly, we probably could. We've only ever filled our fresh tank from clearly marked potable water sources - campgrounds, dump stations and the occasional friendly business or two. We also use the standard blue Camco RV Water Filter on the hose going into our fresh tank. And we have sanitized the tank too.

So why don't we drink it? First, although all the water sources we've used have been marked as potable, you just never know how reliable they are. Second, we've come across a couple of instances where the water had a funny taste - detectable even after it had been boiled for a cup of tea. In the end, it's just an abundance of caution - when it's something as critical as the water you drink, why take a chance?

Our solution thus far has been to carry 1-gallon jugs of drinking water with us. Mostly this has come from the Prima reverse osmosis machines in Walmart stores, but we've also used those standalone RO water stations or particularly trustworthy campground water sources too. We've been carrying 6 of these in a box in the truck, and 1 in the fridge. Good, clean water for usually around $0.30 per gallon. This has honestly been working pretty well for us for 12 months now, and I don't have a problem recommending this approach to us.

Except…there are a few drawbacks with this approach:

  1. Filling up seven 1-gallon jugs is just another chore to deal with, usually on travel days;
  2. Reverse osmosis water is pure - arguably too pure. It actually has most (if not all) minerals removed, so we're missing out on all this goodness in our water;
  3. Our fresh tank is huge (78-gallons) so it seems silly to be carrying another 50lbs of water in the truck for drinking.

In the end, we decided our solution would be to install a very high quality water filter inside our RV, connected to a dedicated faucet just for drinking water. Diana likes drinking room-temperature water so she can take that straight from the faucet, and I prefer mine chilled, so we'll continue to keep a jug in the fridge that I can top up from the faucet.

Which water filter to use?

When you start researching RV water filters, it's not long before the Berkey comes up. Whether it's the Big Berkey, the Travel Berkey, or one of their other models, the idea is the same - it's a countertop filter where you pour water into the top and filtered water comes out of a tap on the bottom.

By all accounts, they're fantastic. In fact, we've not yet met an RVer with one who wouldn't recommend it. The filters are considered industry-leading, capable of removing nearly all viruses, bacteria, heavy metals and other chemicals - check out their test result page for full details. They really are impressive.

But there's one large drawback - their size. Even their smallest, the 1.5-gallon Travel Berkey has a footprint diameter of 7.5" and stands 19" tall. That would consume a huge amount of our valuable countertop space. Plus, it can't just sit on the countertop on travel days, so we'd have to find a place and method to secure it. Sorry Berkey, you won't work for us.

We turned out attention to inline water filters. We've heard fantastic things about the RV Water Filter Store, so that's where we went looking. They propose a three step system to:

  1. Filter the water before it gets into your RV;
  2. Soften the water (if necessary);
  3. Remove other impurities ready for drinking.

For now, we're not concerned about softening the water - it honestly seems like overkill for what we do. And for now, our little Camco RV Water Filter will complete step 1 for us - though I can see us upgrading to something more advanced in future, particularly if we travel through areas with more dubious water sources.

That just leaves step 3: achieving next-level purity for drinking water, using an under-sink filtering system.

We chose to go with their Ultrapure Under-Sink System which uses a very high quality cartridge filter incorporating both Carbon and Ceramic filtration. This means in addition to sediment filtration down to 0.5 microns, it also removes 100% of cysts, 99.9999% of Pathogenic bacteria, >99% of Chlorine, Lead, Herbicides & Pesticides, >98% of VOCs & heavy metals, and many more impurities. After doing our research and reading comparisons of different filter types, we were sold.

Choosing a faucet

Typically, with under-sink systems, the filtered water is made available through a dedicated filtered-water faucet on the countertop. When you buy the Ultrapure Under-Sink System, you can choose from a variety of different faucet styles - Chrome, Brushed Nickel, Antique Brass, White or Oil Rubbed Bronze.

But us being us, we decided to do something different. Remember I said at the top of the post that our main kitchen faucet broke recently? Well, what better excuse did we need to find a clever solution to both problems!

The answer: a double faucet. This is a faucet that has a mixer handle and spout for the regular water, and a separate handle and spout for drinking water - but the difference is that it has a single post. This means it can reuse the existing hole in the countertop, and takes up minimal extra space - perfect!

Except…these are really rare. Home Depot and Lowe's don't sell any at all.

Oh, and I should add, we didn't want just any double faucet - we specifically wanted one with the pull-down hose on the main water spout. Those are even rarer as double-faucets!

We went to one of those fancy kitchen & bathroom showrooms - they had one. For $700. In a catalog. That would take a week to arrive. Erm, nope!

Our savior turned out to be Amazon: we found the WANFAN Modern Pull Down Kitchen Sink Faucet 3 in 1 Water Filter Purifier Faucet Brushed Nickel. In case you're wondering the "3 in 1" refers to hot, cold and filtered water. And although our RV fittings are currently rubbed bronze (or something like that), we're not fans of it and are keen to start transitioning towards something less terrible - like brushed nickel / stainless steel.

WANFAN Modern Pull Down Kitchen Sink Faucet 3 in 1 Water Filter Purifier Faucet Brushed Nickel
This kitchen faucet was the only pull-down faucet with an integrated drinking water spout that we could find anywhere!

The reviews were generally positive, although there were a few complaints about how sturdy it was. Spoiler alert: when I tug hard on the faucet, the entire countertop moves with it, so no concerns there!

So we went ahead and ordered our new kitchen faucet from Amazon, and our Ultrapure Under-Sink system from the RV Water Filter Store, minus the faucet option.

Installing the faucet and filter

The installation itself was very straightforward, with only basic tools required. Depending on your specific plumbing it may vary slightly, but in terms of tools, all we needed was:

  • Screwdriver
  • Crescent wrenches (it was useful to have 2)
  • 10mm wrench (the narrower end compared to the crescent wrench was useful when tightening the fittings)

I used PTFE tape liberally throughout, even though when I removed the existing faucets, I didn't find any had been used - I'm no plumber, but it seemed like a sensible thing to use!

The hot and cold water hoses from the new faucet were terminated with 3/8" female connectors, whereas the old faucet hoses were terminated with 1/2" male connectors. In order to allow the new faucet hoses to mate with our existing hot and cold water lines, I picked up a couple of 1/2" to 3/8" compression fittings from my local hardware store - the compression nut is unnecessary, but that's just what they had. You can also reducing compression fittings on Amazon too, but check your plumbing first to make sure they're necessary / the right size.

I picked these connectors up from our local hardware store, but you can find them online too.

You'll also need 4 screws to mount the water filter in your chosen location, and optionally, I used a couple of 1/2" cable clamps to secure the water lines too.

Clear some space

Water is typically the enemy of RVers, so the last thing we want is water going everywhere. I cleared out the cupboard under the kitchen sink, and also removed the two drawers adjacent to the cupboard to give me good access to the water lines.

We're lucky that in our small RV, the water pump and water heater are right under the kitchen countertop, so I had ready access to all the plumbing I needed.

Turn off the water

We did this install while boondocking (we like to live dangerously!) so we didn't have to worry about disconnecting city water - but don't forget to do that if you are doing this install and are hooked up! Instead, we just turned off the water pump.

Water Pump Switch
Don't forget to switch off your water pump and disconnect from city water (if you're hooked up)!

There is still some residual pressurized water in the lines, so I ran the kitchen tap hot and cold to drain out what I could. Even after this, there is still some water in the lines, so I just prepared the area with a towel to mop up any water.

Removing the existing faucet

After double (and triple) checking the water pump was off, I was able to disconnect the hot and cold water feed lines to the kitchen faucet. I was able to remove both of these by hand - no tools required. Some water dribbled out but it was easily mopped up.

Hot & Cold Water Lines
Have a towel handy to mop up the residual water that will leak from these lines. It also helps to do it when the water heater hasn't been on so you don't burn yourself.

The faucet itself was a little harder. It has a threaded base that goes down through the countertop and mates with a large tightening nut. This nut had two screws in it, putting pressure on a plate up against the underside of the countertop to stop it loosening. At first I tried removing these screws entirely, but my crescent wrench wasn't big enough to remove the large nut.

So I went rogue. I put the screws back in so they were securely threaded in, but not putting pressure on the top plate. Then I hammered the side of these screws with the crescent wrench (yes, it felt as dirty as it sounds) to loosen the nut. Sure enough this worked, and after a turn or two I was able to remove the nut by hand. The nut and screws aren't needed again, so even if they were a little bent or damaged, it didn't matter. If you have a larger crescent wrench or more appropriate tool, this likely won't be an issue for you - but I got it done!

With the nut removed, the faucet was easily lifted out. I took the time to clean around the hole in the countertop to make sure there was no residue left.

Installing the new faucet

The process to install the new faucet is just a reversal of the process to remove the old one. This particular faucet has copper pipes at the bottom into which you screw the short supplied hoses. Before putting the faucet in place, I attached the hoses using PTFE tape in all the connections. I also attached the 3/8" to 1/2" adapters using more PTFE tape, and put PTFE tape on the male ends of all the hoses - it's much easier to do that now than trying to do it in the cabinet under the sink!

The only connection I didn't install was the mixer hose quick connect - with this in place, the new plastic nut won't slide over the hoses because they're too thick.

Installing the new faucet
This large plastic nut is easy to tighten by hand, but take your time wiggling it over the hoses so you don't damage anything.

With all connections prepared, the new faucet just dropped through the countertop, and I secure it from underneath with the supplied rubber washer and large plastic nut - tightening this by hand was straightforward, I just took care to ensure the faucet was aligned nice and straight.

It's worth noting I chose not to use any plumbers putty or sealant on the countertop - I considered it, but the faucet had a rubber gasket that sits on the countertop, and I was confident this was sufficient.

Connecting the mixer hose

With the faucet secured, the mixer hose can be attached. This is as simple as screwing the quick-connector to the copper pipe from the faucet, and connecting the other end of the mixer hose into it.

The mixer hose also has a weight which needs attaching to the mixer hose. Ideally the hose would hang loose, but with our tiny RV under-sink cabinet it kind of spools up on the shelf inside. I installed the weight so it was still hanging and wouldn't quite reach the shelf - this allows plenty of hose to be pulled out of the faucet too.

Mixer Hose Weight
This weight splits into two parts and then slides over the mixer hose. I positioned it so it's still just hanging when the faucet hose is retracted.

Connecting hot and cold water

Time to get some water flowing and check out the new faucet! Hooking up the hot water side is easy - just connect the hot water supply line to the hot water fuse (and adapter) from the faucet.

The cold water side is a little more involved, but not too complex. First task is to attach the T-connector supplied with the water filter kit to the cold water supply line - I used more PTFE tape here. The cold water hose from the faucet connects to the other side of this T-connector.

Ultrapure Under-Sink System Kit
The Ultrapure Under-Sink System is supplied with some PEX hose, a T-connector, a shutoff valve and a PEX connector for the filtered water.

The T-connector has a PEX connection built-in which, per the instructions, should connect via a short length of PEX to a shutoff valve - both the PEX line and shutoff valve are included in the water filter kit. The PEX hose is easy to cut with a pair of scissors, and I installed the shutoff valve with about a 3" length of PEX from the T-connector.

Now, if you've done this right, with the shutoff valve closed you should be able to turn on the water pump and the main faucet should work. This is particularly useful if other occupants of the RV are keen to use the bathroom - I speak from experience.

I tentatively turned on the water pump and listened as the lines pressurized. The water pump stopped. No leaks! I opened the mixer tap on warm, and after the air was purged from the lines, the water came through and there were no leaks under the sink!

I had some spare 1/2" cable clamps lying around, so I used a couple of these to secure the water lines to the wall. Although not necessary, I feel better with these secured rather than flapping around as we drive!

Water Lines Connected
The hot water line is connected directly, and the T-connector and shutoff valve are installed on the cold water line. I clamped the lines to the wall to keep them secure and out of the way when moving.

Installing the water filter

Before we can connect up the water filter lines, we need to mount the water filter itself. Be warned, the cartridge holder is BIG!

I mounted the bracket on the cartridge holder lid, and screwed the cartridge holder into the bottom of the lid. I tried various locations to mount it, remembering that I had to be able to get the supplied tool in to tighten the canister. In the end, I settled on a spot on the wall behind the sink P-trap. Here it is easily accessible but would be somewhat protected by the plumbing.

The water filter kit doesn't provide mounting screws, but I had some 1" screws lying around which worked great. I swear the hardest part of any RV mod is working in the cramped conditions, and screwing that mounting bracket into the wall behind the P-trap is no exception! Removing the canister itself from the lid made mounting the bracket easier.

Water Filter Mounting Bracket
It wasn't easy to reach in behind the sink to install this, but it's well protected now. The screws to attach it to the wall weren't supplied so I used some 1" screws.

Connecting the water lines for the filter is easy. I used scissors to cut some of the supplied PEX tubing to length, and it just press-fits into the connectors. One piece goes from the shutoff valve to the input side of the water filter, and the other piece goes from the output side of the water filter to the filtered water hose on the faucet. Both the faucet and the water filter kit came with an adapter for this, but the one that came with the faucet is the one that fits.

With all the lines connected, I installed the water filter cartridge in its holder, and screwed this into the lid mounted on the wall - tightening it with the supplied plastic wrench. Time to test!

I opened the shutoff valve and listened as water filled the filter cartridge for a few seconds. Then I opened the drinking water faucet and after the air purged, we had filtered water!

Conditioning the filter

Before you can drink the filtered water, the filter has to be conditioned. It comes with full instructions, but essentially you have to run water through the filter for 10 minutes and then leave it to sit overnight.

Remember that part earlier when I said we were boondocking? Running the water for 10 minutes isn't ideal….

Fortunately, our huge fresh tank had plenty of water in - the challenge was just our grey tank capacity. So instead of just running the water down the drain, I collected it for 10 minutes in gallon jugs and emptied it outside.

Testing for Leaks

Since we had to leave the filter to sit overnight before using it, it was a good chance to test the system for any leaks. I made sure to thoroughly dry the shelf under the faucet before bed that night.

Faucet & Water Filter Plumbing
The finished result with the faucet and water filter all hooked up. I left it like this overnight so I could check for leaks in the morning....

The next morning, there were a few small drips on the shelf. A leak - noooooo!

I checked all the connections were tight, and found that the quick-connect adapter for the mixer hose wasn't as tight as it could have been. I tightened it by hand a little more, and tested that the drips stopped. All done - time to put everything back in the cupboards.


We're really pleased with the end result - not only is the new faucet much prettier than the old one, it has a higher rise on it which makes washing up easier. Plus, our shiny new faucet also dispenses fresh filtered water for us too - no more filling and carrying around gallon jugs in the truck!

The filtered water tastes great, and the flow rate isn't too bad - we tested and it took 1 minute 36 seconds to fill a 1-gallon jug. I wouldn't want to fill our entire fresh tank at that speed, but for pouring a glass of water to drink or topping up the jug in the fridge, that's perfect for us.

Double Kitchen Faucet & Ultrapure Water Filter
Doesn't it look pretty? I think the brushed nickel faucet goes really well with our stainless steel sink and other kitchen accessories. Plus, the integrated drinking water spout means no extra holes in the countertop!

Although using RO water in jugs has worked well for us until now, this feels like a real upgrade to life in our RV - and makes it feel just a little less like camping! If you don't want to switch out your faucet like we did, then you can buy the Ultrapure Under-Sink System with a faucet - this installs on the countertop next to your existing faucet.

We'd love to hear from you though - what do you do for drinking water on the road? Do you just drink straight from the fresh tank like some of our friends do? Maybe you use a Berkey? Or if you have an under-sink water filter, how do you like it? Let us know in the comments below!

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