Watering down interior latex paint is often necessary as the paint—in stock form—can be thicker than necessary. Whether you are trying to make the paint stretch further or just trying to make it easier to work with, most interior latex paint can safely be watered down. This is usually a simple task to perform. The result of watering down your paint will be more, thinner paint.
Read the instructions on the paint can. If your interior latex paint is safe to mix with water, there will be instructions for doing so printed on the label. These instructions will include the amount of water to be added per can of paint.
Get a liquid measuring cup for measuring the water. Measuring the water you add is highly recommended—adding too much can make your paint unusable. Adding water by eye is not recommended as it is easy to add too much.
Pour the recommended dosage of water into the paint and mix it in until the paint is of equal consistency throughout. You are now ready to use your newly watered down interior latex paint.