Scenario.
Over at in-las the other week to make a little step down to the patio (aged legs etc)... "Can you fix our water"
"What's wrong with it" "The hot tap's don't work"
Crawl up in loft with torch. Twin header tanks, both empty although CH one was full. Wiggling ballcocks - nothing.
"When did it happen"
"Oh well they were doing work on the mains, and the water all went off, and then it came back all muddy and brown and full of stuff, the cold water works in the sink, but thats all"
Head scratch time. Tied slamming me hand over the kitchen mixer and back flushing the hearer tank...seemed to be enough pressure..couldn';t understand it at all.
I had just about given up when FIL said 'is it anything to do with this' leading me to a cupboard I had never seen before "I don't know what that is, but it never seems to do anything but it has lots of pipes on it" (he's been in the house for 5 years)
And lo and behold there was a softener..complete with isolation valves and a bypass loop.
"Do you ever fill it up with salt or anything" "No. I didn't know I hasd to"
A quick check of the valves immediately resulted in water rushing through the bypass, although the unit stubbornly resisted any attempts to get water to flow through it.
I left it that way, concluding that the shit that had come down the mains had probably blocked the ion exchange unit beyond anything short of a reverse flushing...of course the hot water STILL didn't work, but the good old Mk1 hand slammed over the kitchen mixer with all taps on soon put the air back where it belonged.
I told him to claim for a plumbers call out fee and a new softener from the water company :-)