After repairing a leak in my main water supply line, I have low water pressure throughout the house. When, for example, I turn on the sink, pressure is normal for about five seconds, then it gets progressively weaker. It does not stop altogether, however it is very weak. Clogged line perhaps? If so, is there any thing I can do?

Whenever you disturb the supply lines, oftentimes some debris gets caught in the strainers found at eash of your sinks. Try removing and cleaning them. While they are off, turn on the faucets and flush the lines thoroughly.

If this doesn't help, there may be debris caught in your shutoff valves or they may not be turned on all the way. Pressure will build up, regardless of the size of the opening, but when flow starts, it will reduce. Have a look at the main shutoff at the meter, it may not be on all the way.

There is definitely an obstruction somewhere.