Changing some basic habits will reduce how much water you use from sinks. For example, stop running the water while you’re brushing your teeth or shaving. In fact, it is better to fill the sink with about an inch of water to rinse your razor than to wash it under a running tap.
You should also install water aerators on all your faucets. This will maintain water pressure but cut your water usage in half. Like water-saving shower heads, water aerators cost little and are easy to install.
If you need your kitchen sink to wash dishes (for instance, you don’t own a dishwasher or you have some dishes that you need to wash by hand), try to minimize your water use. For a start, don’t keep the water running as you wash. If you have double basin, soap dishes in one and keep the other full of water for rinsing. If you have single basin, soap all your dishes and then rinse everything at once with a spray or dual-switch aerator on your faucet.