Snake your drains
An average bathroom sink is 6-7 litres
The water could be turned off under the sink or at some other point in the supply line.The pipe could have become clogged with rust or other impurities.The faucet could be operating improperly and not opening. (A washer that has broken and blocked the piping.)The screen filter over the faucet could be filled with small gravel or rust.If you have no water flow it is the aerator or both pipes are frozen (located on an outside wall)The possibilty of both H&C being blocked with internal corroson is NIL for both to stop the supply at the same time
Most times a bath / lavatory sink will stop water flow because of hair that accumulates in the trap of the drain ,The trap is the upside"S"underneath the sink ...Try using liquid plumber foaming pipe snake that you can buy at your favorite grocery store.
Place some towels under the sink to catch any drips while doing this procedure. Turn off the valves under the sink that supply water to the faucet. Disconnect the supply lines to the faucet. Place a bucket under the drain pipe. Disconnect the p-trap. Drop the trap into the bucket. The mechanics of the sink have been disconnected now the sink needs to be removed. If it is a pedistal sink, look for screws or bolts unterneath by the faucet. I've installed in vanity, those sinks are usually glued to the cabinets. Use a prybar to separate it. http://www.lets-do-diy.com/Projects-and-advice/Bathroom/Basins-and-bidets.aspx
remove aerator
A typical bathroom sink uses around 1.5 to 2.5 gallons of water per minute when the faucet is running.
Snake your drains
You will have a shut off for the commode and each sink. The only way to turn the supply to the shower is to turn off the supply to the entire home.
The mesh filter at the head of the faucet is clogged. Take it off, clean thoroughly and re-install.
Unscrew the aerator from the end of the faucet where the water comes out and clean the screen. Sediment build up slows the flow.
Supply lines- Hot and cold water for each sink, bathtub, Jacuzzi tub, and shower. Cold water for each toilet. Drain lines- one for each sink, bathtub, Jacuzzi tub, shower, and toilet.
There could be several reasons why water from a bathroom sink tastes like fecal matter, including sewage contamination in the water supply, a buildup of bacteria or algae in the pipes, or a malfunctioning water filtration system. It is important to contact your local water provider to investigate the issue further and ensure the water is safe to drink.
Replace the faucet.
Did you remember to turn the supply line back on? Was there a plug that needed to be removed before connecting it?
The average kitchen faucet in a house will supply 2.5 -3 gallons per minute at 50 PSI. That is an average hose working pressure in north America. A large bath faucet will supply 3 + gpm and a single lever bathroom sink faucet will be about 2 gpm.
Check the shut-off valve for the hot water side that's under the sink and make sure it's fully open.BECAUSEThe installer did NOT remove the aerator prior to the installation and the flow restrictor is blocked