Softener drain into dry-well (soak pit)

I am in the process of running 2" drain 20' in length from my laundry room to a dry well (soak pit made of fabric, gravel). The drain will receive ONLY softener waste, heat pump water heater condensate and water heater pressure relief with the lines simply strapped to the wall and funneled into the drain. Questions:

Do I need to install a vent or tie into an existing one with this set-up? ..or can i live without it. Obviously it drains fine right now but I don't have the terminated end of the drain buried in gravel yet. I am wondering if that would change once I fill the dry well with gravel and cover with dirt.

Do I need a p-trap?
If the only purpose is to prevent sewer gas, I don't believe I will have any due to the type of water and the frequency of drainage.

Only other benefit I can see is to keep pests from crawling up the drain pipe and into the building. If I am correct in my thinking that I don't need a p-trap, is there an alternative way to keep insects from crawling up through the pipe?


Softener regens 1x per 7 days
Water heater trickles five gallons 1x per two-three weeks

The problem with gravel drains for softeners is that the accumulation of salt in the area of the end of the drain will stop it from working in the not too distant future. I'm not saying a softener gives off a lot of salt, but in the backwash process. the excess salt is flushed to drain.
Here in Florida, most of the drains go directly on the ground or into the sewer.

speedbump said:

The problem with gravel drains for softeners is that the accumulation of salt in the area of the end of the drain will stop it from working in the not too distant future. I'm not saying a softener gives off a lot of salt, but in the backwash process. the excess salt is flushed to drain.

Here in Florida, most of the drains go directly on the ground or into the sewer.

Click to expand...

Add back-flush from an iron and/or charcoal filter and it will preset problems. At some point solids are going to build up.

Discharge on the ground? Isn't the grass sparse enough down there already?

rafjr64 said:

Do I need a p-trap?

If the only purpose is to prevent sewer gas, I don't believe I will have any due to the type of water and the frequency of drainage.

Only other benefit I can see is to keep pests from crawling up the drain pipe and into the building. If I am correct in my thinking that I don't need a p-trap, is there an alternative way to keep insects from crawling up through the pipe?

Click to expand...

Maybe a swing check valve but it would have to be installed on a true horizontal ideally with an inspection port to make sure it stays closed and for service.

Most septic tank installs do not have back-flow valves.

...uh...

I guess the check valve could be installed in the basement/house...

Thanks fellas. There is a gutter drain in the same area (4" solid pvc). I guess I could tap into it if you think that is wiser. More area/volume in the gutter drain system so the case for a p-trap just got stronger as well huh?
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Questions:

Can I place the swing style check valve on the 2' standpipe in the laundry room? Also seems it would have to be a very lightweight spring to allow the water heater condensate to escape. Are those rated in pounds or pressure?

Vent: As long as I don't seal all of the joints where the gutter downspouts enter the drain pipe, I don't need a vent on this system...is this correct? I must have 6-8 gutter downspouts on this home.

Discharge on the ground? Isn't the grass sparse enough down there already?

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You wouldn't believe how fast the grass grows here in the summer months. I mean weeds. Of the multitude of weed varieties I have the salt doesn't seem to phase them in any way. What the salt would do to real grass like Bahia or St. Augustine I couldn't say. I don't have any!

rafjr64 said:

Questions:

Can I place the swing style check valve on the 2' standpipe in the laundry room? Also seems it would have to be a very lightweight spring to allow the water heater condensate to escape. Are those rated in pounds or pressure?

Vent: As long as I don't seal all of the joints where the gutter downspouts enter the drain pipe, I don't need a vent on this system...is this correct? I must have 6-8 gutter downspouts on this home.

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Use a sump pump check valve. It can be mounted either horizontally or vertically.

It will keep all varmints and midget submarines out. Mount inside for easy service.

Is this p-trap installed correctly?

http://www.flickr.com/photos/19642395@N04/28013544572/in/dateposted-public/

Whatever and however you do it, never drain your backwash drain into your septic.

rafjr64 said:

Is this p-trap installed correctly?

http://www.flickr.com/photos/19642395@N04/28013544572/in/dateposted-public/

Click to expand...

Yes it is installed correctly. But, the drain bowl itself is for condensate drainage (HVAC - WH - TPRV -etc) where an air gap(s) must be maintained.

If introducing a pressured drainage (water softener - back-flush filters - washing machine), it may be best (IMO) to drain that into a standpipe with less chance of backup or splashing.

If you decide to go with a P-TRAP, the back-flow valve shouldn't be needed as it will become a gravity fed drain and code must be followed there for drain pipe slopage.