Pool is about 40 years old. I have been maintaining the pool (oth than liner replacements (3 so far) for 20 years. it was nice to see the water level about half way up the skimmers when taking off the winter cover a couple of weekends ago. All seemed well after spring equipment resuscitation. Pump started fine, filter got fed DE, bottom skimmed with a net and robot tossed in. All looked fine again when the summer cover was rolled out eight hour later.
Saturday seemed nice enough to try a bit more serious cleaning. The pool water was fairly clear - I was thinking thank goodness no heavy brushing to the tune of Song of the Volga Boatmen.
Then it struck me that the water level was below the lip of the scupper. A run down to the equipment pad did not reveal any significant leaks. One union had a small drip but surely didn’t drain down hundreds of gallons over a couple of weeks. We had other things to do and by the time we returned home it had started raining. I put some painters tape at the water level to see if the leakage had stopped.
Sunday morning it was discovered that the water level had dropped another 3/4”. It occurred to me that the pool seemed to hold water over the winter so perhaps the liner was fine. I plugged scuppers and returns and refilled to 1/2 way up the scuppers, again marling the water level with painters tape.
Monday - water level was maintained thank goodness. What might be best steps to take next? If the shell isn’t leaking and there is no evidence of leakage around the exposed pipes or equipment, then that leaves underground pipe? At the equipment pad there is only a single suction and single return pipe coming out of the ground. There are two scuppers and two returns in the pool, so I can open either the return system or the suction system.
Assuming that one or the other will be identified as the compromised system, what might be a good strategy for affecting an underground repair?
Thanks in advance for sharing thoughts.

Saturday seemed nice enough to try a bit more serious cleaning. The pool water was fairly clear - I was thinking thank goodness no heavy brushing to the tune of Song of the Volga Boatmen.
Then it struck me that the water level was below the lip of the scupper. A run down to the equipment pad did not reveal any significant leaks. One union had a small drip but surely didn’t drain down hundreds of gallons over a couple of weeks. We had other things to do and by the time we returned home it had started raining. I put some painters tape at the water level to see if the leakage had stopped.
Sunday morning it was discovered that the water level had dropped another 3/4”. It occurred to me that the pool seemed to hold water over the winter so perhaps the liner was fine. I plugged scuppers and returns and refilled to 1/2 way up the scuppers, again marling the water level with painters tape.
Monday - water level was maintained thank goodness. What might be best steps to take next? If the shell isn’t leaking and there is no evidence of leakage around the exposed pipes or equipment, then that leaves underground pipe? At the equipment pad there is only a single suction and single return pipe coming out of the ground. There are two scuppers and two returns in the pool, so I can open either the return system or the suction system.
Assuming that one or the other will be identified as the compromised system, what might be a good strategy for affecting an underground repair?
Thanks in advance for sharing thoughts.
