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What changes could come from changing my plumbing pipes?

My water supply comes in through a 3/4" pipe and then shrinks to a 3/8" pipe that supplies water to my faucets, tub, washer, etc. If I change the pipes to be consistently 3/4" will I be able to have: Better water pressure? Better water distribution (to avoid lack of pressure when showering and having the washer running simultaneously)? Also, if pressure is increased, provided all other fixtures remain the same (and that the time spent using water [i.e. a 10 minute shower] does not change), will my water consumption increase and cause my water bill to potentially increase?

Public Comments

  1. You don't want to change to bigger pipes. By going bigger, you decrease the water pressure, thus using more water. Water coming into your house in the 3/4 pipe is usually set at around 30-40 psi. By making the pipes smaller to the fixtures, you create more pressure which will have two pluses. First, you will have more pressure while taking a shower, which is always good. And the other is you will use less water.
  2. By increasing the tubing size you will actually drop the water pressure. If you have galvanized pipe then you may be able to switch to the same size copper tube and get better water pressure. I would have to know what the supply pressure from the city main is in order to tell you the required line sizes but what you have seems ok for residential plumbing.
  3. You wont increase pressure as such, but you could increase flow (there is a difference). If you use an appliance for 10 minutes at a rate of 7 l/min then increase the flow to 9 l/min then yes you will use more water and increase your bill. The main advantage would be noticing slightly less fluctuation in pressure if more than on appliance is used at the same time.
  4. from my experience if you change size up pipe it would most definitely change water pressure and usage i had a pipe freeze and break in basement last winter it was the hot water line so i changed it only. Before if i had hot and cold both half open the water was warm after that because the cold had a larger line the water was still pretty cold if they were both half open to get it warm i had to open cold like quarter the way and hot half way
  5. Upgrading your pipes to 3/4" will give you consistently better water flow throughout your house. That means that when someone flushes a toilet, you will be less likely to be scalded or frozen in the shower. The effective pressure at each fixture, when water is flowing, will improve. The upgrade should not increase water consumption all by itself. With better water flow you may have to change your habits about how far you open the valve when showering, though. When I built our house, I used PVC and CPVC water pipe. I ran a 1" cold water line and a 3/4" hot water line in parallel down the middle of the house. The hot and cold legs to the water heater are exactly the same length. We can wash clothes, dishes, and flush a toilet, and take a shower and it all works.