Organic material may be precipitated by the use of alum in the form of an alum-borax mixture. The sediment should be allowed to settle and the water may then be drawn from the top.

To remove organic matter, for each gallon of water 1 tablespoon of a mixture made up of two-thirds borax and one-third alum should be used. If the water is rich in organic matter, more than 1 tablespoon of the mixture must be used. When water is very scarce, alum is sometimes used to separate the dirt from the water and the water is then filtered and used again.