Like most RVs, our motorhome has a wet bay where one hooks up the incoming fresh water supply and drains the gray and black waste tanks. Our wet bay came with an electric hose reel, and a single filter for water quality.

Here’s what it looked like:

For a while, I’ve had an external water softener to deal with hard water in various parts of the country, and a three-stage water filter system:

But lugging those in and out of a storage bay every time we changed campsites was a bit of a pain. So I came up with a plan to get them both mounted inside the coach, so I don’t need to do that each time.

I engaged Dillon Massey of DC Plumbing & General Repair in Red Bay, Alabama to do this for me.

Here’s a rough sketch that I drew, to help explain my plan to Dillon:

A little complex, perhaps, but it seemed logical to me. The hose from the campground faucet would be attached to a connector in the wet bay, then would split to a built-in black tank flush valve and a hose to the water filters mounted in a cargo bay. The water would then go from the filters to a three-way valve to the water softener and a connector for backflushing or regenerating the water softener, with another three-way valve and connector after the softener, then on to the existing systems.

The idea of the two three-way valves and connectors was to have water normally flow from the filter through the softener and onwards, but by turning the valves and attaching an input hose to the first connector and an output hose to the second connector, I could regenerate the softener, where one adds salt to it and flushes it out (without getting salt in the rest of the system), a maintenance process I need to do every couple of weeks in hard water areas. Or by reversing those hoses, I could backflush the softener, i.e. have water flow in the reverse normal direction only through the water softener, something I need to do every three months.

These enhancements were admittedly unusual; Dillon had mounted water softeners in wet bays many times before, but had never before done valves and connectors like this to backflush and regenerate. Normally, people would disconnect and remove the water softener when doing those servicing operations, but I wanted to be able to do it more easily.

In preparation for the work, while staying at Red Bay Acres, I cleared out the plumbing bits from the wet bay and nearby cargo compartment:

Dillon removed panels at the top of the wet bay, moved the electrical outlet, and removed the hose reel, which I didn’t want anymore, both to provide space for the water softener, and because I didn’t use it anyway; I preferred to connect a more flexible hose:

The removed panels; I had the idea to reverse them from how they were before, which provided more space in the wet bay, enabling adding salt to the water softener more easily (compare the picture of the wet bay at the start of this post to how it looks at the end of this post):

There wasn’t room in the wet bay for the three-stage water filters, so my plan was to install them in the nearby cargo bay, mounted on the wall (to avoid interfering with the cargo slide):

Here are the fllters installed there, with hoses connecting to the wet bay:

He also added a valve to connect the water system directly to the black tank flush, so I don’t need to connect a hose to rinse out the black tank, though the valve is a little hard to reach:

The three-way valves and connectors; unfortunately the spacing wasn’t ideal, so the left valve only barely cleared the right connector, but it was usable:

Dillon’s mods completed, with new three-way valves and connectors installed in the top panel, the water softener mounted inside the wet bay:

Unfortunately, when I tested the connections later, I discovered that they didn’t match my specifications. Here’s a sketch over a picture of the wet bay, showing how I suspected that the connections were misconfigured:

This meant that while it was fine in the normal (horizontal) valve positions, when turning the valves to the regen/backflush positions (vertical), the left one would connect between the incoming water and the connector, instead of the water softener input and connector. And similarly, the right valve would connect between the rest of the coach and the connector, instead of the water softener output and connector, as it should.

So I sketched how I want to fix that, plus also rearranging the valves and connectors to make them fit better, and adding an easier to reach valve for the black tank flush:

While at NIRVC in the DC area, I got them to make those changes:

They successfully reversed the positions of the left valve and connector, though couldn’t rotate it 90° as requested, so instead trimmed the valve handle to fit better in the space.

Regenerating the water softener involves adding two containers of salt to the top of the unit, which I can do without having to remove it from the wet bay:

Here are the valves in the regenerating configuration, with the input hose connected on the left and the output on the right:

And here are the valves in the backflushing configuration, with the input water on the right, and output on the left:

Much easier. Unfortunately, this saga isn’t quite over: while this works, filling the water tank gets really slow after regenerating. I suspect that the water filters are in the incorrect place in the circuit, so they are getting clogged with the salt. We’ll be back in Red Bay in December, so I’ll get Dillon to investigate and fix it then. In the meantime, I’ll have to disconnect the output of the water softener and connect a hose to it, to avoid this issue. Annoying, but not too difficult.

And when doing that, I discovered that even with the water pump on, no water would flow inside the coach when diverting the softener output. Which tells me that these modifications are after the tank, not before as they should be. The way I designed it, using the valves shouldn’t have any impact on pumping water from the tank into the coach.

Finally, here’s the normal configuration of the valves, where water flows through the filters and softener into the coach. Notice also the new black tank flush valve in the upper-left, that makes it super easy to rinse out the black tank (we kept the valve Dillon installed too, just visible in the lower-right, as a backup):

And notice also the normal water input connector:

I really appreciate not needing to lug the water filters and softener every time we change campsites. And while the regeneration and backflush options still aren’t quite right, I still think they were an excellent idea; I look forward to them working as designed.

Update: after much investigating, I determined that the valves and connectors were okay, just reversed from how I specified. So I was able to simply rotate the water softener, so the input and output were reversed, and swap the labels on the new valves, and now the system works properly. Yay!