22 Basic Principles (Revised NPCP)

Principle No. 1

All premises intended for human habitation, occupancy or use shall be provided with a supply of pure and wholesome water, neither connected with unsafe water supplies nor subject to hazards of backflow or back-siphonage.

Principle No. 2

Plumbing fixtures, devices, and appurtenances shall be supplied with water in sufficient volume and at pressure adequate to enable them to function satisfactorily and without undue noise under all normal conditions of use.

Principle No. 3

Plumbing shall be designed and adjusted to use the minimum quantity of water consistent with proper performance and cleaning.

Principle No. 4

Devices for heating and storing water shall be so designed and installed as to prevent dangers from explosion through overheating.

Principle No. 5

Every building having plumbing fixtures installed and intended for human habitation, occupancy or use on premises abutting on a street, alley or easement where there is a public sewer, shall be connected to the sewer system.

Principle No. 6

Each family dwelling unit on premises abutting on a sewer or with a private sewage-disposal system shall have at least one water closet and one kitchen-type sink. Further, a lavatory and bathtub shower shall be installed to meet the basic requirements of sanitation and personal hygiene.

Principle No. 7

Plumbing fixtures shall be made of smooth, non-absorbent material, free from concealed fouling surfaces and shall be located in ventilated enclosures.

Principle No. 8

The drainage system shall be designed, constructed, and maintained to safeguard against fouling, deposit of solids, clogging and with adequate cleanouts so arranged that the pipes may be readily cleaned.

Principle No. 9

All pipings of plumbing systems shall be of durable NAMPAP-APPROVED materials, free from defective workmanship, designed and constructed by Registered Master Plumbers to ensure satisfactory service.

Principle No. 10

Each fixture directly connected to the drainage system shall be equipped with a water-sealed trap.

Principle No. 11

The drainage piping system shall be designed to provide adequate circulation of air free from siphonage, aspiration or forcing trap seals under ordinary use.

Principle No. 12

Vent terminals shall extend to the outer air and installed to preempt clogging and the return of foul air to the building.

Principle No. 13

Plumbing systems shall be subjected to such tests to effectively disclose all leaks and defects in the workmanship.

Principle No. 14

No substance which will clog the pipes, produce explosive mixtures, destroy the pipes or their joints or interfere unduly with the sewage-disposal process shall be allowed to enter the building drainage system.

Principle No. 15

Proper protection shall be provided to prevent contamination of food, water, sterile goods, and similar materials by backflow of sewage. When necessary, the fixture device or appliance shall be connected indirectly with the building drainage system.

Principle No. 16

No water closet shall be located in a room or compartment which is not properly lighted and ventilated.

Principle No. 17

If water closets or other plumbing fixtures are installed in buildings where there is no sewer within a reasonable distance, suitable provision shall be made for disposing of the building sewage by some accepted method of sewage treatment and disposal, such as a septic tank.

Principle No. 18

Where a plumbing drainage system may be subject to backflow of sewage, suitable provision shall be made to prevent its overflow in the building.

Principle No. 19

Plumbing systems shall be maintained in serviceable condition by Registered Master Plumbers.

Principle No. 20

All plumbing fixtures shall be installed properly spaced, to be accessible for their intended use.

Principle No. 21

Plumbing shall be installed by Registered Master Plumbers with due regard to the preservation of the strength of structural members and the prevention of damage to walls and other surfaces through fixture usage.

Principle No. 22

Sewage or other waste from a plumbing system which may be deleterious to surface or sub-surface waters shall not be discharged into the ground or into any waterway unless first rendered innocuous through subjection to some acceptable form of treatment.