In reply to message posted by Andrei:
Couple of days ago we found that we run out of hot water pretty quick – we have solar heater. It’s exactly the same now – no hot water after sunset. We can hear the noise (of running water..well, sort of; it sounds like water running in a pipe, probably louder) between the walls (?) with all taps closed and water meter is moving slowly. We suspect (but not sure) that we have a leak (between the walls ?) What is the best way to check it and/or find exact place of leaking ?
If you have a water meter shut off all the faucets in the house and look at the meter dial.
Then shut the water supply to the solar heater and see it it stops the meeter from moving.
If it does then you can try to trace the lines and see the exact location GOOD LUCK