Water Softner Backwash... is this okay?

[Threehappypenguins]

We had two "water specialists" come by today because we wanted to hear what their plans were with regards to water softener setup and backwash. We already decided that we absolutely will not permit the backwash to be tied into our (very small) septic system. We will likely do the work ourselves (have enough experience). For clarity, I created this graphic to try and explain what they want to do:

We have a 1986 split entry home where our basement is only about halfway into the ground (the kind with the pony walls throughout). We live in Nova Scotia, where we do get freezing weather in the winter, but usually it hovers around 0 C most of the winter, sometimes dipping to -10 C, and very rarely more than -20 C. The frost line is usually about 3 ft below ground, but every so often (very rarely) we get a deep freeze where the frost line is like 5 feet down (happened a few years ago and some people had an issue with their septic tanks freezing).

The first guy wants to go from the tubing to 3/4" drainage pipe, and then have that come out our wall just above the concrete, and point down toward a 4" sewer pipe (they would not actually be connected, so there would be an air gap. Then the sewer pipe go a couple of feet below ground, turn to the right, and run paralell to the house, past it about 4' and to an underground gravel pit (but not an actual dry well).

The second guy pretty much wants to do the same thing, only from the tubing to a 1 1/2" drainage pipe to a 3" pipe to catch the water and go under ground.

Something like this shouldn't freeze, right? Which way is better? First? Second? A combo of both? Neither? Also, is a full dry well really necessary? Or is just a bunch of gravel in its place okay? It's a huge pain to dig in my area, as it's very rocky and you end up pulling up a ton of boulders and big rocks as you go.

 

[Reach4]

Slope your horizontal 3/4 pipe downward. Put a vacuum breaker in the high part of that drain line so that the line will empty.

and to an underground gravel pit (but not an actual dry well).

That's normally called a dry well. What do you call a dry well?

 

[Sponsor]

 

[Threehappypenguins]

Slope your horizontal 3/4 pipe downward. Put a vacuum breaker in the high part of that drain line so that the line will empty.


That's normally called a dry well. What do you call a dry well?

I thought a dry well was a little contraption that the water goes into underground, which is subsequently surrounded with gravel? Like this?

 

[Reach4]

https://en.wikipedia.org/wiki/Dry_well

 

[Threehappypenguins]

We looked everything over today to make plans for plumbing, and thought that it would be a lot easier to make a longer run for the backwash throughout the heated envelope of the house, and then come out the side of the house to a 4" sewer pipe so we only have to dig a trench that's 4' long to go past the house (instead of a much longer trench outside).

We want to run the drainage up along the ceiling, then go back down and out the far wall just above the concrete. As you can see, the upper half is wood covered with drywall, the lower half is concrete (covered with spray foam insulation).

So that leaves me with a few questions...

The total drainage run inside would be about 24' 10". From concrete floor to ceiling (bottom of the joists) is 7' 6" (though the softener drainage I don't think comes from floor level; we don't have the softener system yet).

On Inspectaepedia, it says this:

Water softener drain line routing: Keep the water softener drain piping as short and low as possible: less than 30 feet in length and no more than 8 feet above the floor level.

The drain line must be of adequate diameter to handle the water conditioner's backwash flow rate. Use a 3/4" diameter pipe if the drain flow is more than 7 gpm.

We are going to be getting a 2 cubic softener system (60K grains). I believe it says something about outputting 10 GPM. I assume that also means for backwash? Not sure. But isn't what comes out of the softener system a 5/8" tubing? At what point would we transition to at least a 3/4" drainage pipe? Would it be mainly 3/4" pipe we would put along the ceiling? The length and height of the drainage is sufficient in our case, right?

 

[Threehappypenguins]

Slope your horizontal 3/4 pipe downward. Put a vacuum breaker in the high part of that drain line so that the line will empty.

I'm just seeing this comment now, for some reason (didn't notice before). So I would have a long slope toward the wall where it exits? How much of a slope? Also, why would I need a vaccum breaker, if the pipe is open outside and just drops into the 4" sewer pipe? Wouldn't that itself be a vacuum breaker?

 

[Reach4]

So I would have a long slope toward the wall where it exits? How much of a slope? Also, why would I need a vaccum breaker, if the pipe is open outside and just drops into the 4" sewer pipe?

Imagine a soda straw with your finger on it. You can lift that out of the glass, and it will hold water. By letting air in, the water can run out rather than sitting there and potentially freezing.

 

[Threehappypenguins]

Imagine a soda straw with your finger on it. You can lift that out of the glass, and it will hold water. By letting air in, the water can run out rather than sitting there and potentially freezing.

So going with the straw analogy, the vacuum breaker would be at the water softener tank, then? It would function as "taking your finger off the straw," with the pipe opening outside of the house acting as the end of the straw where you want the water to come out?

 

[Reach4]

So going with the straw analogy, the vacuum breaker would be at the water softener tank, then? It would function as "taking your finger off the straw,"

Ideally the vacuum breaker is at the high point on the pipe.

 

[Threehappypenguins]

Ideally the vacuum breaker is at the high point on the pipe.

So then either anywhere along the ceiling, or just before it drops down to go outside?

 

[Bannerman]

A VB will allow air to enter the downstream line when there is negative pressure (vacuum) downstream of the VB. Locating the VB just before the line drops down to go outside will allow that 'drop down' section to drain which will be OK.

Suggest keeping the run from the softener slightly lower than the intended VB location so the run will need to rise slightly to enter the VB. This will keep the long run before the VB filled with water which will be less likely to trickle out slowly through the VB as that water may freeze in the downstream line outside the heated space.

 

[Threehappypenguins]

A VB will allow air to enter the downstream line when there is negative pressure (vacuum) downstream of the VB. Locating the VB just before the line drops down to go outside will allow that 'drop down' section to drain which will be OK.

Suggest keeping the run from the softener slightly lower than the intended VB location so the run will need to rise slightly to enter the VB. This will keep the long run before the VB filled with water which will be less likely to trickle out slowly through the VB as that water may freeze in the downstream line outside the heated space.

I found the manual for the control valve that we're interested in (Autotrol 255/760), and in it, it states:

The drain line must be a minimum of 1/2-inch diameter. Use 3/4-inch pipe if the backwash flow rate is greater than 7 GPM (26.5 Lpm) or the pipe length is greater than 20 feet (6 m)

and

If the backwash flow rate exceeds 5 gpm (22.7 Lpm) or if the unit is located 20-40 feet (6.1-12.2 m) from drain, use 3/4-inch (1.9 cm) tubing. Use appropriate fittings to connect the 3/4-inch tubing to the 3/4-inch NPT drain connection on valve.

So at this point I have to figure out what the backwash flow rate will be. I'll probably contact the manufacturer because I don't know how to determine the rate. But it does look like I have to use at least 3/4" drain just based on the run being longer than 20 feet, and it sounds like it needs to be straight from the tank (no 5/8" tubing at all).

So with the amendments:

Does that look right? I was doing more reading, and I saw that a p trap is recommended in some applications. Would a p trap be necessary here? Or maybe we could keep the long run straight (vacuum breaker same height as the beginning of the long run as I originally had) and have the p trap instead so that it's always filled with water. I read that an air lock (I think that's the word) of some kind may be necessary?

 

[Reach4]

1. No p-trap.

2.Try to slope the cold horizontal some.

3. I think 3/4 pvc or cpvc or pex is more likely than 3/4 abs.

Have you identified a potential vacuum breaker?

 

[Bannerman]

So at this point I have to figure out what the backwash flow rate will be.

For a softener, the backwash flow rate will be mainly determined by the diameter of the softener's media tank. A softener containing 1 cubic foot (1 ft3) of resin (32,000 grains total capacity), will be typically installed in a 9" diameter tank so the usual backwash rate will be 2.0 GPM.

For 1.5 ft3 resin (48,000 grains total) will typically be installed in a 10" diameter tank which will most often utilize 2.4-2.5 GPM for backwash.

For 2.0 ft3 resin (64,000 grains total) installed in a 12" diameter tank = 3.5 GPM.

The words 'typical', 'usual' and 'most often' are stated as some softener dealers will install 1 ft3 resin in a 10" diameter tank. The backwash rate is also influenced by incoming water temperature as the backwash rate will need to be increased if the incoming water temperature is warm which is unlikely in your location.

If you are considering a softener equipped with an Enpress Vortech bottom plate, the backwash rate will also be less than stated above.

 

[Threehappypenguins]

Have you identified a potential vacuum breaker?

Whoops. Sorry. I meant to also share a link for a VB I found. Would something like this work?

2.Try to slope the cold horizontal some.

Forgive me if this is a dumb question, but... what do you mean by trying to slope the "cold horizonal"?

3. I think 3/4 pvc or cpvc or pex is more likely than 3/4 abs.

D'oh, you're right. The standard drainage pipe in our house is 1 1/2" black ABS. So yeah, if I'm doing 3/4", then it's gonna be PVC or CPVC.

 

[Reach4]

Whoops. Sorry. I meant to also share a link for a VB I found. Would something like this work?

That is what I was thinking. I had looked through the instructions to see if there was a limit for orientation. You read and see what you think.

Forgive me if this is a dumb question, but... what do you mean by trying to slope the "cold horizontal"?

I meant the horizontal pipe that is not in the heated area.

 

[Threehappypenguins]

For a softener, the backwash flow rate will be mainly determined by the diameter of the softener's media tank. A softener containing 1 cubic foot (1 ft3) of resin (32,000 grains total capacity), will be typically installed in a 9" diameter tank so the usual backwash rate will be 2.0 GPM.

For 1.5 ft3 resin (48,000 grains total) will typically be installed in a 10" diameter tank which will most often utilize 2.4-2.5 GPM for backwash.

For 2.0 ft3 resin (64,000 grains total) installed in a 12" diameter tank = 3.5 GPM.

The words 'typical', 'usual' and 'most often' are stated as some softener dealers will install 1 ft3 resin in a 10" diameter tank. The backwash rate is also influenced by incoming water temperature as the backwash rate will need to be increased if the incoming water temperature is warm which is unlikely in your location.

If you are considering a softener equipped with an Enpress Vortech bottom plate, the backwash rate will also be less than stated above.

I found more info. This is the softener that we want to purchase. If you click on the "Specs" tab, you will find something that says "Continuous service flow rate of 15.5 GPM with a backwash of 6 GPM."

 

[Threehappypenguins]

That is what I was thinking. I had looked through the instructions to see if there was a limit for orientation. You read and see what you think.

I found this pdf, and I did try Googling about "orientation," but I have no idea what that means. Like, whether the VB faces up, down, or sideways?

I meant the horizontal pipe that is not in the heated area.

So you're talking about sloping this part (area circled)?

If so, which way should it slope? Going upward? Or downward? And why?

 

[Threehappypenguins]

Just had another guy come over for a quote, and he also doesn't do the outside work, but he did have some interesting suggestions. He said to rent a hammer drill to drill through the concrete below the frost line, then tie some PEX or whatever for drainage into the weeping tile (I think that's what he called it?) that would be around the perimeter below our foundation. We would also rent a mini excavator to dig down to the weeping tile. This would ensure that we would never have to be concerned about freezing nor would we need to be concerned with digging a trench and build a dry well.

Thoughts?

 

[Reach4]

If so, which way should it slope? Going upward? Or downward? And why?

Slope so that water runs out, and does not pool and freeze.

Just had another guy come over for a quote, and he also doesn't do the outside work, but he did have some interesting suggestions. He said to rent a hammer drill to drill through the concrete below the frost line, then tie some PEX or whatever for drainage into the weeping tile (I think that's what he called it?) that would be around the perimeter below our foundation.

Where does that water go?