Luke explained the water usage.
Rafael listened.
Then examined the pool and its equipment.
He reviewed the available records, checked the normal operating conditions, and asked whether Luke had noticed any other changes.
Luke thought for a moment.
"Sometimes I hear a low vibration near the back fence."
Rafael looked toward the landscaping.
"When?"
"Usually late afternoon."
"Does it happen when your normal pool equipment is running?"
Luke frowned.
"That's the strange part. Sometimes it continues after the regular cycle ends."
Rafael nodded slowly.
He examined the equipment enclosure.
Then the decorative tile line near the pool's eastern wall.
For several minutes, he said little.
Finally, he looked toward Luke.
"This pool has an older auxiliary line."
Luke nodded.
"I remember seeing that in the inspection report."
"Do you know whether it was ever connected to an outdoor water feature?"
"Not since I've owned the house."
Rafael studied the records again.
Then said, "I want to verify where that line actually goes."
Luke frowned.
"Why?"
The technician looked toward the fence.
"Because an unexplained flow path could account for some of what you're seeing."
He didn't accuse anyone.
He didn't claim to have found a deliberate connection.
But he recommended a more thorough professional assessment, including appropriate isolation and observation of the older plumbing.
Luke agreed.
He was concerned about the cost.
But he was more concerned about allowing an unknown problem to continue.
The original owner of Luke's house had been an architect named Samuel Whitaker.
Samuel built the swimming pool in the late 1990s, when Cedar Ridge Estates was still under development.
He loved water features.
His original backyard design included a modest fountain that circulated water near the pool.
A decorative channel also ran toward a landscaped garden.
The features were later removed.
Some plumbing was abandoned.
Other components were replaced or capped during renovations.
The surviving records described the auxiliary system only briefly.
When Luke bought the house, the fountain was gone.
The garden had been redesigned.
And the pool functioned normally through its modernized filtration system.
There was no reason for him to believe the old line was being used.
But Rafael's questions made him curious.
Luke searched through the property folder supplied by the seller.
He found the original pool construction invoice.
A rough equipment sketch.