I had to call on a Sunday afternoon at 12:30pm to get a plumber out to clear out a stopped up drain in the basement of a rental property. I got a person on the phone right away and she told me someone would be available between 2pm and 4pm - I got a call back at 1pm saying the on-call plumber was on his way. It wasn't cheap by any means (what plumber is?) but I was able to get someone over on a Sunday within an hour of calling and he fixed the problem in 90 minutes.
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