This section is from the book "Practical Real Estate Methods For Broker, Operator & Owner", by Thirty Experts. Also available from Amazon: Practical Real Estate Methods for Broker, Operator, Owner.
Filters in the larger apartment houses are a desirable addition, their use being a convenience to the tenant as well as a sanitary precaution. In addition to this, in twelve-story houses they help to eliminate dirt and other foreign matter from the water supply, thereby insuring better circulation and less deposits in the pipes and traps of the plumbing system throughout the house. Filters are easy and inexpensive to maintain if properly made and installed. A cheap filter, however, is worse than useless. One criticism that can be made of the use of a filter is that it reduces the water pressure, thereby increasing the necessity for the use of a pump, but in buildings over six stories in height the pump is practically a necessity. Therefore, this question may be disregarded in buildings more than six stories high.
Note should be taken of such additional equipment as wall safes, which are of little practical use, of mail chutes, which are of great convenience and cost nothing to maintain, of garbage closets, which find favor with many tenants, but which must be carefully and often cleaned to be kept sanitary.