Interesting Drain Connection

I came across this yesterday.

It took me a few minutes to figure it out. Why was there a PVC pipe coming up out of the ground, doing a 180, and then dump into an opening to the drain pipe?

Looking in crawl space, I could see where the drain pipe connected into the main drain line out to the sewer. But the PVC pipe didn’t appear to come from anywhere in the house. There is no sump pump. Then I realized, it ties to to the pool equipment, in case you want to drain the swimming pool!

Anyone ever see this set up before?

I can’t imagine with the Southern California heat the p-trap would keep water in it.

At least a good gap 1"+ so there no back syphon - cross connection issues.

Like this? It was in a crawlspace, no air gap.

I don’t think it’s legal to dump the entire content of a pool into the sewer system.

Just curious, as I’ve not heard this before.

From what I mostly see, if one drains their pool, they have no choice but do it into the street, which either goes to the sewer anyway, or (depending on where you are) directly out to the ocean without going to a treatment plant.

OK, I had to look it up:

Of course, local codes will vary.

Good to know. The storm drains here go right to the ocean without any treatment, typically, there might be some exceptions. It probably varies per location as to whether it is legal or not.
This is what San Diego says about cleaning the filter…
“How do I clean pool filters? It’s best to clean the pool filter over a lawn, planter
box, vegetated hillside or something that absorbs the discharge. Collect materials
on filter cloth, then throw the filter cloth away. Back washing or acid cleaning is
not allowed into the storm drains. All filter backwash fluids must be discharged
into the sanitary sewer via a legal sewer connection, and the backwash fluids must
have a pH between 5 and 12.5 before discharging into a sewer connection. See
manufacturer’s specifications for information on how to check pH.”
Pool water into the storm drain is basically the same as L.A.

LA City does not allow draining of pools into the public sewer system…