Basic Plumbing Principles

Del. Code tit. 16, ch. 79
in effect

Del. Code tit. 16, § 7901 Purpose.

The basic plumbing principles contained in this chapter shall act as the basis for the formation of all detailed plumbing regulations adopted by the Division of Public Health, local or district boards of health or city councils.

Del. Code tit. 16, § 7902 Principles applicable throughout State.

All plumbing installed after June 4, 1949, in any part of the State shall conform to the basic plumbing principles provided in this chapter.

Del. Code tit. 16, § 7903 Plumbing Code; adoption and enforcement.

The Division of Public Health shall adopt and enforce the most recent version of the International Plumbing Code (IPC) within 1 calendar year of its issuance, in conformity with the basic plumbing principles provided in this chapter. The Division of Public Health may adopt and enforce additional plumbing regulations which shall not be in conflict with the IPC and the basic plumbing principles set forth in this chapter.

Del. Code tit. 16, § 7904 Local regulations.

Every political subdivision within the State, including county, city or municipal governments, shall enforce the International Plumbing Code (IPC) as adopted or modified by the Division of Public Health. Every political subdivision retains the right to propose additional or modified plumbing regulations, which must be submitted in writing to the Division of Public Health for review and approval. The Division of Public Health, within 60 days of receiving such proposed changes or additions, shall consult with the State Board of Plumbing, Heating, Air Conditioning, Ventilation and Refrigeration Examiners, and may thereafter adopt, modify or reject the proposed changes or additions. Upon issuance of the statewide plumbing regulations every political subdivision shall have the option of adopting and enforcing said regulations, or adopting and enforcing the minimum standards set forth in the most recently adopted version of the IPC.

Del. Code tit. 16, § 7905 Additional regulations.

Nothing in this chapter shall be construed to limit the Division of Public Health, councils of cities or sanitary bodies of communities from making further and additional regulations not in conflict with this chapter.

Del. Code tit. 16, § 7906 Rules and regulations for installation of plumbing; registration of plumbers; application for inspection.

(a) The Division of Public Health, in order to provide for the health of the citizens of the State, shall adopt and promulgate suitable rules and regulations for the construction, alteration, repair, modification or renovation of water and sewer systems and of building and house drainage systems; shall enforce those rules and regulations; and shall make provisions under this section and Chapter 18 of Title 24 for the punishment of any person who violates or assists in the violation of or refuses to comply with such rules and regulations. (b) Registration and licensure of plumbers and persons engaged in the practice of plumbing in this State shall be in accordance with Chapter 18 of Title 24. (c) No license shall be required of a person who installs such person’s own plumbing work, service or equipment in or about such person’s own home that is not for sale or any part for rent or lease, except that such person shall be required to obtain a permit from the Division of Public Health or from the proper plumbing inspection authority. Nothing in this subsection (c) shall be construed to prohibit a person from obtaining free assistance in installing such person’s own plumbing work, service or equipment in such person’s own home that is not for sale or any part for rent or lease. (d) Property used exclusively for agricultural purposes is excluded from all provisions of this section, except for the necessity to obtain a permit from the Division of Public Health or from the proper plumbing inspection authority. (e) The Division of Public Health shall issue plumbing permits and shall assess a $100 fee for each permit, except that no permit shall be required or fee assessed for the replacement of an existing fixture, piece of equipment or related piping, including but not limited to hot water heaters and water conditioning systems. All revenue generated shall be retained by the Division of Public Health in order to defray costs associated with the plumbing inspection program.

Del. Code tit. 16, § 7907 Inspection and inspectors.

(a) The Division of Public Health shall by rules and regulations also establish a system of inspection and supervision over all water and sewer systems, building and house drainage systems and ventilation of the same. (b) The Division of Public Health shall appoint such inspectors as may be necessary, at such compensation as may be fixed by it, and shall make provision for payment of same. (c) All plumping inspectors must be practical plumbers with at least 10 years’ experience and skilled and well trained in matters pertaining to plumbing and sanitation generally. (d) All plumbing inspectors shall, as far as may be necessary for the performance of their duties and the maintenance of the health of the citizens of the State, have the right to enter any building or premises in the State. They shall have the right to inspect and order the removal of any plumbing fixture, soil, drain, waste, vent pipe or pipes, cesspools, septic tanks and privies when they, at the discretion of the inspectors, are deemed in an unsanitary condition. (e) A $50 inspection fee per inspection shall be assessed when the Division of Public Health inspectors must conduct any inspection due to the permittee’s failure to comply with applicable regulations after 3 inspections. All revenue generated shall be retained by the Division of Public Health in order to defray costs associated with the plumbing inspection program.

Del. Code tit. 16, § 7908 Definitions.

As used in this chapter: (1) “Place of public entertainment” shall mean an establishment that accommodates more than 100 individuals. (2) “Plumbing” is the art of installing in buildings the pipes, fixtures and other apparatus for bringing in the water supply and removing liquid and water-carried wastes. (3) “Plumbing fixtures” are receptacles intended to receive and discharge water, liquid or water-carried wastes into a drainage system with which they are connected. (4) “Plumbing system of a building” includes the water supply distributing pipes, the fixtures and fixture traps, the soil, waste and vent pipes, the house drain and house sewer, the storm water drainage, and all the devices, appurtenances and connections of the above within or adjacent to the building. (5) “Public restroom” shall mean a public sanitary facility that contains more than 1 plumbing fixture.

Del. Code tit. 16, § 7909 Safe water supply.

All premises intended for human habitation or occupancy shall be provided with a supply of pure and wholesome water.

Del. Code tit. 16, § 7910 Cross connections with unsafe water supplies.

(a) Cross connections between safe and unsafe water supply distributing systems shall not be permitted unless such connections have the written approval of the Division of Public Health. (b) No plumbing, fixture, construction, valves, fitting, device, apparatus or connection that will provide a cross connection between a safe water supply and a sewage system or will permit or make possible the back flow of sewage or waste into a water supply system shall be installed.

Del. Code tit. 16, § 7911 Adequate water supply.

Buildings in which water closets and other plumbing fixtures exist shall be provided with a supply of water adequate in volume and pressure for flushing purposes.

Del. Code tit. 16, § 7912 Size of pipes.

The pipes conveying water to water closets shall be of sufficient size to supply the water at a rate required for adequate flushing without unduly reducing the pressure at other fixtures.

Del. Code tit. 16, § 7913 Hot water tanks or boilers.

Devices for heating water and storing it in boilers or hot water tanks shall be so designed and installed as to prevent all danger of explosion and also prevent a back flow of hot water through a meter connected with a public water supply.

Del. Code tit. 16, § 7914 Separate sewer connections.

Every building intended for human habitation or occupancy on premises abutting on a street in which there is a public sewer shall have a separate connection.

Del. Code tit. 16, § 7915 Family private water closet in multiple dwellings.

In multiple dwellings provided with a house drainage system there shall be for each family at least 1 private water closet.

Del. Code tit. 16, § 7916 Plumbing fixture materials.

Plumbing fixtures shall be made of smooth nonabsorbent material, shall be free from concealed fouling surfaces and shall be set free of inclosures.

Del. Code tit. 16, § 7917 House drainage system.

The entire house drainage system shall be so designed, constructed and maintained as to conduct the waste water or sewage quickly from the fixture to the place of disposal with velocities which will guard against fouling and the deposit of solids and will prevent clogging.

Del. Code tit. 16, § 7918 Drainage pipes.

The drainage pipes shall be so designed and constructed as to be proof, for a reasonable life of the building, against leakage of water or drain air due to defective materials, imperfect connections, corrosions, settlements, vibrations of the ground or building, temperature changes, freezing or other causes.

Del. Code tit. 16, § 7919 Cleanouts in drainage systems.

The drainage system shall be provided with an adequate number of cleanouts so arranged that in case of stoppage the pipes may be readily accessible.

Del. Code tit. 16, § 7920 Fixture traps.

Each fixture or combination fixture shall be provided with a separate, accessible, self-scouring, reliable, water-sealed trap placed as near to the fixture as possible.

Del. Code tit. 16, § 7921 Adequate air circulation.

The house drainage system shall be so designed that there will be an adequate circulation of air in all pipes and no danger of siphonage, aspiration or forcing of trap seals under conditions of ordinary use.

Del. Code tit. 16, § 7922 Roof terminals, soil or waste stacks.

The soil stack shall extend full size upward through the roof and have a free opening, the roof terminal being so located that there will be no danger of air passing from it to any window and no danger of clogging of the pipe by the frost or by articles being thrown into it or of roof water draining into it.

Del. Code tit. 16, § 7923 Water or air pressure test.

The plumbing system shall be subjected to a water or air pressure test and to a final test in such manner as to disclose all leaks and imperfections in the work.

Del. Code tit. 16, § 7924 Substances entering house drainage system.

No substance which will clog the pipes, produce explosive mixtures or destroy the pipes or their joints shall be allowed to enter the house drainage system.

Del. Code tit. 16, § 7925 Connections with refrigerators.

Refrigerators, ice boxes or receptacles for storing food shall not be connected directly with the drainage system.

Del. Code tit. 16, § 7926 Light and ventilation.

No water closet or urinal shall be located in a room or compartment which is not properly lighted and ventilated to the outer air.

Del. Code tit. 16, § 7927 Private sewage treatment and disposal system.

If water closets or other plumbing fixtures exist in buildings where there is no sewer within reasonable distance, suitable provision shall be made for the disposing of the house sewage by some method of sewage treatment and disposal satisfactory to the health authority having jurisdiction.

Del. Code tit. 16, § 7928 Back flow of sewage.

Where a house drainage system may be subjected to back flow of sewage suitable provision shall be made to prevent its overflow in the building.

Del. Code tit. 16, § 7929 Storm water.

Storm water from roofs and paved areas, yards, courts and courtyards shall be drained into a storm water sewerage system or a combined sewerage system, but not into a sanitary sewerage system intended for sewage only. Inside roof leaders, downspouts and storm water house drains shall be designed and constructed as are other drainage pipes.

Del. Code tit. 16, § 7930 Privy vaults.

Privy vaults or cesspools shall not be permitted on premises accessible to a public sewer.

Del. Code tit. 16, § 7931 Private water supply.

Dug wells or other sources of private water supply shall not be permitted on premises accessible to a public water supply unless the private water supply has been approved in writing by the Division of Public Health.

Del. Code tit. 16, § 7933 Public accommodations.

In any place of public entertainment required by a state, county or municipal law, rule or regulation to have a public restroom, water closets and urinals shall be provided in accordance with the minimum number of plumbing facilities required under the 1993 National Plumbing Code promulgated by the Building Officials and Code Administrators International, Inc. (BOCA), Table P-1204.1, Building Use Groups A-1, A-2, A-3 and A-5.

Del. Code tit. 16, § 7934 Backflow.

(a) For purposes of this section: (1) “Backflow” means the movement of water back in the direction from which it was flowing. (2) “Backflow preventer” means a device that prevents backflow. (3) “Backsiphonage” means backflow caused by negative pressure, which occurs when there is a drop in water pressure resulting in the water flowing back into the water service line. (4) “Low hazard building” means a building in which any backflow that does occur meets the following conditions: a. Occurs only by backsiphonage. b. Does not create a health risk or health hazard. c. Does not disrupt the service of piped water for human consumption or impair the potability of that water. d. Does not pose a risk to any fresh water supply. e. The pumping system involved does not connect to a treatment system used to convey wastewater, fertilizers, or chemicals, or that is used to provide fire protection. f. The water system involved does not draw from more than 1 aquifer without a backflow preventer on the discharge line of each well. (b) Subject to subsection (c) of this section, a county or municipality may not require backflow preventers to be installed or, if already installed, to be subject to inspections, in low hazard buildings of any of the following types: (1) Single-family residences. (2) Single-family residences with conditional uses that permit professional offices. (3) Professional offices. (4) Commercial buildings. (c) If a low hazard building has fresh water supplied by a public well, backflow preventers must be installed in compliance with 7 DE. Admin. Code, Regulation 7301, governing the construction and use of wells.

Del. Code tit. 16, § 7935 Penalties.

Whoever violates or assists in the violation of this chapter or any order, code or regulation issued under this chapter shall be, for each offense, fined not less than $25 nor more than $100 or imprisoned not more than 60 days, or both.
Source: DE Code (Official Site)URL: https://delcode.delaware.gov/title16/c079/index.htmlFetched: 6/28/2026

Starting a business in Delaware? Delaware LLC guide: costs and requirements