Apologies in advance for the length, just trying to get it all out there.

As a part of our In-ground pool build, they built (~15 years ago) a ground level pool deck, The deck surrounds the pool and extends up to the house (picture a large patio off of the house.)

In the deck, drain holes where installed, and a drain trough was installed along the house where the deck abuts the house.

All these drains, and I would imagine any overflow line or lines coming from the pool are ties back to an underground 4" drain that extends from the backyard to the front street curb.

For the last few days, I've noticed a stream of water out of that drain into the street. Sometimes it's just barely a dribble, and I've even seen it where it looks like it has stopped.

But over the last few days it keeps reappearing.

Just this afternoon, I walked out to the curb, the "stream" was there. I them walked over to look at our water meter, The needle indicating water was running in our house was spinning.
But at that time, I was the only one home and there was no water running in our house at the time. No toilets flushing, no washing machine one, etc.

The pool level appears fine, the water is still (no ripples).

Could there be a pool drain valve, and overflow valve, etc. near the pumps and filter that is partially open?
Perhaps the valve on the far lower left side of our equipment, that 90s into the ground, with the label just to its right - "POOL RETURN".

Sorry. I'm just not that familiar with the pool plumbing configuration.

Thank you very much for any advice.

If your pool level isn't going down, then my first guess is an autofill issue. The first thing I'd do is shut that off and see if the problem stops*. If it does, then you know it's the autofill. The autofill should be located somewhere near your pool and look like a skimmer, inside the autofill there is an adjustable float that may need to be adjusted so it turns off once the pool is to its correct level (similar to how a toilet tank fills up). If you don't have an autofill, then its unlikely that the issue is with the pool since the water level isn't dropping.

*sounds like you may not be familiar with this....there are several ways that an autofill can be plumbed, the most common that I've seen are a valve at the pool equipment that looks similar to a hose spigot valve (it may also be a ball valve) with a 1/2" to 1" pipe coming up and going back into the ground, if this is your situation, just turn the valve off. It can also be spliced off a nearby hose spigot. Either of these there should be an inline backflow device. Another way is it is plumbed into the sprinkler system, you should shut off your sprinkler system, easiest way is shutting the valve at the backfill device.

This happens to me where sometimes my auto fill will keep running slowly and I will see water running down my gutter. It just so happens that my pool drains to the curb through the same pipe as my French drains for my yard. This can make it a bit tough to distinguish between pool water and sprinkler water. If the curb is still wet in the afternoon, then I know it's pool water. Sometimes I have to just turn the auto fill spigot off for a bit and then turn it back on, or adjust the autofill float.

Between this thread, and my submission on Trouble Free Pools, believe I've identified the components to address.

Must say, it's kind of funny to find out a product normally associated with a toilet is used for pools. But then again, thinking about what goes on in pools sometimes ...

Thanks all.

Snowmaggedon in 2021 jacked our auto-fill up. Later that spring/summer we noticed an area of our lawn and flowerbeds that was constantly wet, muddy, growing algae, etc. We thought it was a drainage issue from lawn watering but it was the pool overflow.

When the pool froze over, it slightly bent the arm of the ballock on the autofill. It wouldn't shut off until the water was already over the pool drain.

Created such a slow trickle that over time it started flooding the yard near the overflow drain outlet (hidden by grass around it) but not such a trickle that we noticed on the water bill. When the irrigation company came to look he found the issue in about 1 minute and noted it was enough over time to cause the flooding, but not enough flow to be more than $10 or $20 a month on our water bill, therefore unnoticed.

Between the comments here, a pool forum, and YouTube, was able to identify the problem and a resolution.

Replaced a Fluidmaster # 242 seal ($3.48 + tax @ Lowe's). Took al of about 5 minutes.

YouTube on replacing the seal (457) Toilet Fill Valve Not Shutting Off / Don't Replace / Fix Fast Cheap & Easy For Beginners - YouTube

Putting this out there hoping it could help others at some point.