NO FLOW? CHECK FOR CRUD

Whether it's water coming in or going out, it needs to flow. If the water exiting the faucet is slow it could be a clogged aerator, the screen that attaches to the end of the faucet.    SEE PHOTO

Once cleaned the flow will return to normal. Same applies to shower head screen and washing machines with an in-line filter.

As for drains, the leading cause of a plugged drain is hair. Look into the drain and if the cross member is clogged with hair, pull out the hair mass with a pair of needle nose pliers or other similar tool. Check the drain by opening the taps and notice the flow. If the obstruction was completely removed the water should quickly travel down the drain. There should be no pooling of water in the basin regardless of how open the taps are.

Once a month run some degreaser though all your drains to keep them flowing smoothly.

NOTE: In older homes with steel pipes (supply and drain) rust can build up inside the pipe, restricting flow. Sometimes the corrosion is so bad it causes perforation which may become worse if the pipe is disturbed.