I'm planning to finally deal with the hard water in my home. Before I get a plumber involved, I wanted to check if I could DIY the installation, so here I am.

The water main pipes and valves are exterior to the home adjacent to the garage. After that, the only pipes on the outside of the walls are on the opposite side of the garage as seen in the picture below when entering/exiting the water heater.

Am I able to turn off the main, cut into the inlet seen in the picture, redirect that to a water softener next to the water heater, and then feed the outlet of the water softener back into the water heater? Or am I stuck having to cut through drywall at a closer point to the main?

I'm also not sure what to do about draining the water softener because there's nothing nearby that could take it. There's no floor drain or egress from the garage. The closest thing would probably be the laundry drain lines behind the drywall near the attached picture.

Is it common to have to dig through walls to plumb for a water softener?

garage water heater

  • Where does that top relief valve of the water heater go? Just onto the ground? The inlet side is the one with the red valve, right?
    – JPhi1618
    Feb 10, 2020 at 20:00
  • 3
    This plan would only provide soft water for the HOT water side of your home. It's typical to soften all the internally used water. You need to find where the feed to the water heater splits from the cold water supply line and tap in there.
    – jwh20
    Feb 10, 2020 at 20:01
  • @jwh20, I think it's also pretty common to soften the hot side only. That's what this person was going to do earlier today.
    – JPhi1618
    Feb 10, 2020 at 20:03
  • 4
    @JustinSkiles Perhaps your home is different (I doubt it) but most of those things you have mentioned get BOTH hot and cold water separately. If you look under your sink you will see TWO supply lines, one HOT and one COLD.
    – jwh20
    Feb 10, 2020 at 20:09
  • 1
    Outside taps are cold water only, and if you use any hose-operated sprinklers, you probably don't want to waste money softening that water. Plus, salty water is not what plants crave.
    – JPhi1618
    Feb 10, 2020 at 20:17

1 Answer 1


Yes, a DIY is feasible, provided you don't want whole-house soft water, just soft "hot water". The valve is for your cold water intake (a safety feature that should be on all water heaters), and you'll cut that line and rework it into your water conditioner, taking the outlet of your conditioner back into your water heater cold inlet. You'll keep a cold cut off valve (but probably not the same one), placing it between the wall and your water conditioner.

If you want your cold water to be soft too, you need an exterior softener between the house and the whole house cut off valve. I'd recommend avoiding DIY for an exterior job, as fixes are more complicated if things go wrong.

Even though it is feasible, there are many reasons you might not want to do this job:

  1. It's water, and good PVC joints are made with dry pipe. This means a lot of drying is involved, and rework of mistakes take a long cycle of shut off water, remove, dry, add, turn on water, test (and hopefully not repeat).
  2. Some jurisdictions permit water heater work as DIY, some require a permit, some require a licensed plumber. It's not fun getting fined if you are discovered to be on the wrong side of your city's, county's, state's code. Permit doesn't mean no-DIY, but it does mean committing to a DIY that passes code.
  3. Should things go wrong, you don't have the convenience of someone else's insurance / wallet / time to effect the repairs. One example of something going wrong might be breaking the in-wall pipe attempting to rework the cold water line. Depending on where the break is, you might be DIY'ing drywall too.
  4. This kind of work seems easy and fast, but often it takes more time than expected.

If you've rebuilt a toilet, installed a sink, and fixed an AC drain line, you're primed to replace a water heater, and are primed to do this job. If you've replaced a water heater, this is not more difficult, but there are more cuts and bends involved. If this is your first plumbing DIY it's still within the realm of feasibility for some (demeanor, etc.) while it could be a very challenging DIY for most. If you're on the fence try draining, flushing, and filling your water heater to get a taste of about 1/4 the work.

Good installations have wall mounted pipe, good hoses for where they are required, and a good (tested) drainage system to catch the leaks and spills for canister changes.

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