This is caused by the shut off valves not being turned on, a lack of pressure through one of the shut off valves or an obstruction in one of the supply lines feeding water to the faucet.
- Make sure both shut-off valves are fully turned on.
- Check both the supply lines from the shut-off valves to the faucet. These supply lines need to deliver full pressure to the faucet. If the supply lines do not deliver full pressure, then the faucet will not produce full pressure. The plumbing of the home would need to be investigated for a resolution.
- If the issue is still not resolved, then the cartridge (for one-handle faucets) or cartridges (for two-handle faucets) would need to be removed (or replaced) and the valve body would need to be flushed and cleaned.