Write the next sentence in this paragraph:

How to choose an under the sink water filter
Make sure you have room under your sink for a filter.
The filter will attach to the pipes beneath the sink, so clear enough space to accommodate the filter system.
Understand your water composition.
Before you choose a filter, you will need to know what kind of impurities are present in your natural water supply. Buy a do-it-yourself water testing kit to determine what you want to filter out of your water.