Spa return draining to pool, water level dropping.


LifeTime Supporter
Apr 22, 2013

In ground pool with attached spa, at least ten years old, installed by previous homeowners...

The attached spa was dropping to the level of the pool water every time the pump shut off and I was "intermittently" losing water from the pool when the pump was running. I looked at the check valves and other common causes.

I eventually noticed that the return jets in the spa wall are right at the level that the spa water was settling, so I assume air was entering the spa lines and creating a slow leak through the backwash seals.

I replaced all the unions and couplers on the pressure and return side at the pool equipment, replaced all of the diverter valves and added an extra check valve to stop water draining out of the pump basket and losing prime. I relocated the check valve that was originally only above "return no.2" and installed a new one before both spa returns.

Still didn't stop the spa draining.

I then ran water under pressure down each spa return line and found only one line is going to the spa, (return no.3 on the photo) the other (return no.2) returns to the pool....

This explains why it always seemed I was heating the pool water as well as the spa water regardless of the diverter valve placement.

Is there any reason it would have been installed this way and would I have any issues if I just capped that return line?

TLDR: Realized spa return no.2 is draining in to my pool, not to the spa, should I cap it off to prevent water loss?

Thanks so much!

(please excuse all the excess purple primer, it was getting late!)


  • poolreturn.png
    351.4 KB · Views: 23


Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
Southern OK
I would connect spa 2 back into pool return so you can heat just the spa and the 2 will stop leveling each other... :)


Mar 4, 2020
I have a similar type of situation; After 24 hour bucket test (1/8 inch due to evaporation), main pool leaking 3/8 inch with Pump Off; Main pool leaking 7/8 in with Pump ON; SPA has 5 jets; 4 are SPA return lines; the other jet is a return line from Pool/SPA overflow; added a plug to the overflow jet. Main pool stabilized; SPA leaking about 1 inch/24 hours. Performed a dye test; no apparent leak from SPA jets or SPA Suction. I have a company stopping by tomorrow to perform a pressure test; hopefully it is something minor like what you described above. i will keep you posted. Richard
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.