INDIRECT WASTE PIPE A waste pipe that does not connect directly with the drainage system, but that discharges into the drainage system through an air break or air gap into a trap, fixture, receptor or interceptor.
INDIVIDUAL SEWAGE DISPOSAL SYSTEM A system for disposal of domestic sewage by means of a septic tank, cesspool or mechanical treatment, designed for utilization apart from a public sewer to serve a single establishment or building.
INDIVIDUAL VENT A pipe installed to vent a fixture trap and connects with the vent system above the fixture served or terminates in the open air.
INDIVIDUAL WATER SUPPLY A water supply that serves one or more families, and that is not an approved public water supply.
INTERCEPTOR A device designed and installed to separate and retain for removal, by automatic or manual means, deleterious, hazardous or undesirable matter from normal wastes, while permitting normal sewage or wastes to discharge into the drainage system by gravity.