text: At your home, a water utility supply line into your home is typically only 1 inch in diameter.  This 1 inch pipe is split multiple time to route water to every watter connection in your home i.e toilet, shower, sink, outside faucet.  Each of these connections is typically only 1/2 inch...so the more open lines a home has the lower the pressure will be, as the incoming pressure from the water company is held fairly constant.