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My kitchen was remodeled and I noticed since then the water pressure for new area has been low (hot and cold). Previously we had one sink and dishwasher, now we have

  • Two Sinks
  • Dishwasher
  • Instahot
  • Fridge
  • Spigot running to outside

The line serving the original sink was 1" -- drawn down to 1/2" in the crawlspace and then up to the sink. They extended the 1/2" in the crawl space in the following way - pipe1: first sink (hot and cold) - which then T's to - pipe2: fridge (cold only) - pipe3 (hot) : goes to sink #2 hot and dishwasher - pipe3 (cold) : goes to sink# cold and instahot - pipe4 (continues from pipe3 cold) : runs to spiggot

Could the water pressure issue be related to using the 1/2" pipe to connect to every outlet? Should 1" been run to each location and then each reduced to 1/2" closer to outlet?

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I would expect the water pressure to be lower than it was only if you are running water from multiple outlets simultaneously on the new 1/2" circuits. Otherwise, I would suspect a blockage, possible by excessive cement (if using CPVC) where the new pipes were connected to the old pipes. In any event, I think you should get the contractor or plumber back out to check it for you. It sounds like a construction mistake. But I don't think it has anything to do with the size of the pipe. – getterdun Jan 21 '14 at 2:56
I think your water pressure should be the same. Your flow rate would be less. Could that be what you're seeing? Also if your previous sink was very old it might not have had the water saving features newer fixtures have. – OrganicLawnDIY May 12 '14 at 5:38

Your problem is caused by the plumber down sizing your piping to 1/2". This acts as a restriction to water flow. Replacing the 1/2" piping with 3/4" or 1" pipe will resolve your pressure and flow problems.

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