My house had some of the plumbing replaced with polybutylene 30 years
ago. A couple of years ago, I found drips at a couple of elbows under
the house. I put a pail under on so I could monitor it by ear.
One was below the kitchen sink. It had been less than a drop a second.
A few days ago, it was about ten. It was coming from the floor, at
There's a shelf below the sink, 4" above the floor. The space between
is inaccessible. I shut off the hot water at the heater. That slowed
it. I shut off the water to the house. Before long, the dripping
stopped. I turned the house water back on and got about one drip per second.
That meant the cold pipe was leaking, besides the hot. The pipe fit
pretty snugly where they came up through the shelf. There was no
moisture on the shelf. I pulled the pipes up about an inch and felt the
pipes and connections. I didn't feel any moisture.
This was bizarre. There shouldn't have been any connections between the
shelf and the floor, but apparently both pipes were leaking in that
space. Most alarming, a beam made from a log, possibly a century ago,
had become wet.
In a repair like that, there were a lot of places I could go wrong. I
turned on the water long enough to fill some containers for drinking,
cooking, and washing. I filled a bucket to flush the toilet. I shut
the water off and called a plumber.
I took him to the kitchen to examine the fittings. He replaced the pipes
with PEX and the plastic valves with what looked like chrome-plated
brass. He said they were better than the plastic valves I'd had.
He found no deterioration in the pipes. He said connectors above the
shelf must have leaked. He blew into the pipes but couldn't find a
leak. He said anyway, replacing the fittings was good because that
plastic got brittle. He tried to demonstrate but couldn't break one.
When he left, I discovered that he'd taken the old pipes. I'd wanted to
get to the bottom of the mystery. If the FBI wouldn't investigate the
leaks, I would have used my neighbor's compressor.
The next day I found a drip from an elbow he'd put in, under the house.
The shelf under the sink had been dry 12 hours after he left, but now
there was a puddle. Feeling he wet pipe, I find that the source was the
compression connection at the top of the valve. I took it apart and
found that the chromed brass that the plastic compression was supposed
to seat against, was bumpy. So much for the superiority of metal valves.
I got it to seal with plumber's grease.
I can't figure it. The original leaks were much faster. Logically, I
knew they had to be above the shelf, but I could find no moisture.