Idaho Administrative Code
Title IDAPA 24 - Occupational and Professional Licenses, Division of
Rule 24.39.20 - RULES GOVERNING PLUMBING
Section 24.39.20.600 - IDAHO STATE PLUMBING CODE

01. Section 105.3 Testing of Systems.

02. Section 218 Definitions. Delete definition of "Plumbing System." Incorporate definition of "Plumbing System" as set forth in Section 54-2604, Idaho Code.

03. Section 401.2 Qualities of Fixtures. Replace with the following: Plumbing fixtures must be constructed of dense, durable, non-absorbent materials and must have smooth, impervious surfaces, free from unnecessary concealed fouling surfaces.

04. Section 403.3 Exposed Pipes and Surfaces. Delete.

05. Section 408.5 Finished Curb or Threshold. Delete the last sentences of the first paragraph and replace with the following: The finished floor of the receptor must slope uniformly from the sides toward the drain not less than one-eighth (1/8) inch per foot (20.8 mm/m), nor more than one-half (1/2) inch per foot (41.8 mm/m).

06. Section 408.7.5 Tests for Shower Receptors. Delete.

07. Section 409.4 Limitation of Hot Water in Bathtubs and Whirlpool Bathtubs. Delete.

08. Table 501.1(1) First Hour Rating. Delete Table 501.1(1).

09. Section 503.1 Inspection of Chimneys or Vents. Add the following to the end of section 503.1: Water heating appliances using Category 3 or 4 exhaust venting must be tested in its entirety with five (5) pounds of air for fifteen (15) minutes. Plastic vents must be constructed using manufacturer's instructions.

10. Section 507.2 Seismic Provisions. Delete.

11. Section 507.13 Installation in Garages. Replace 507.13 with the following: Any plumbing appliance or appurtenance in residential garages and in adjacent spaces that open to the garage and are not part of the living space of a dwelling unit must be installed so that burners, burner-ignition devices or other sources of ignition are located not less than eighteen (18) inches (450 mm) above the floor unless listed as flammable vapor ignition resistant.

12. Section 603.2 Approval of Devices or Assemblies. Delete last paragraph.

13. Table 603.2 Backflow Prevention Devices, Assemblies and Methods.

14. Section 603.4.2 Testing. Delete last sentence.

15. Section 603.5.7 Outlets with Hose Attachments. Delete and replace with the following: Potable water outlets with hose attachments, other than water heater drains, boiler drains, freeze resistant yard hydrants and clothes washer connections, must be protected by a nonremovable hose bibb-type backflow preventer, a nonremovable hose bibb-type vacuum breaker, or by an atmospheric vacuum breaker installed not less than six (6) inches (one hundred fifty-two (152) mm) above the highest point of usage located on the discharge side of the last valve. In climates where freezing temperatures occur, a listed self-draining frost-proof hose bibb with an integral backflow preventer or vacuum breaker must be used.

16. Section 603.5.12 Beverage Dispensers. Delete and replace with the following: Potable water supply to, carbonated beverage dispensers must be protected by an air gap or a Reduced Pressure Principle Backflow Prevention Assembly in accordance with ASSE 1013. For carbonated beverage dispensers, piping material installed downstream of the backflow preventer must not be affected by carbon dioxide gas. Potable water supply to beverage dispensers and coffee machines must be protected by an air gap or a vented backflow preventer in accordance with ASSE 1022.

17. Section 603.5.17 Potable Water Outlets and Valves. Delete.

18. Section 603.5.21 Chemical Dispensers. Add the following new section 603.5.21: The water supply to chemical dispensers must be protected against backflow. The chemical dispenser must comply with ASSE 1055 or the water supply must be protected by one of the following methods:

19. Section 604.10.1 Tracer Wire. Add the following exception: Where the electrical wiring for the pump is installed in the same trench as the water line, from the point of origin to the structure, a tracer wire is not required.

20. Section 605.6.2 Mechanical Joints. Add to the end of the section the following: Listed PE (polyethylene), one hundred sixty (160) psi minimum, water service and yard piping may be installed within a building (above ground and below ground) with one (1) joint, provided that only listed and approved metallic transition fittings must be used. Polyethylene (PE) plastic pipe or tubing and fitting joining methods must be installed in accordance with the manufacturer's installation instructions.

21. Section 609.1 Installation. Delete the following sentence: Building supply yard piping must be not less than twelve (12) inches (305 mm) below the average local frost depth; and replace it with the following: The cover must be not less than forty-two (42) inches (1068mm) below grade.

22. Section 609.4 Testing. Deleting the phrase "Except for plastic piping," at the beginning of the third sentence and add the following sentence at the end of the section: Plastic piping is to be tested in accordance with manufacturer's installation standards.

23. Section 609.10 Water Hammer. Does not apply to residential construction.

24. Section 609.11 Pipe Insulation. Delete.

25. Table 610.3 and Appendix Table A 103.1. Change fixture unit loading value for both public and private for bathtub or combination bath/shower, and clothes washers to two (2) fixture units.

26. Section 610.2 Pressure Loss. Add the following: All new one (1) and two (2) family residences built slab on grade or that will have a finished basement at the time of final inspection must have a pre-plumbed water softener loop. The kitchen sink must have one (1) hot soft line and one (1) cold soft line and one (1) cold hard line. Exterior cold hose bibbs intended for irrigation purposes must be piped with hard water.

27. Table 611.4 Sizing of Residential Softeners. Amend Footnote 3 to read: Over four (4) bathroom groups, softeners must be sized according to the manufacturer's standards.

28. Section 612.0 Residential Sprinkler System. Add the following to the end of the first sentence in section 612.1: and the requirements of the Authority Having Jurisdiction (AHJ).

29. Table 702.1 Drainage Fixture Unit Values (DFU). Change fixture unit loading value for clothes washers, domestic for private to two (2) fixture units.

30. Section 703.1 Minimum Size. Add the following at the end of section 703.1: No portion of the drainage or vent system installed underground, or underground under concrete must be less than two (2) inches in diameter.

31. Section 704.2 Single Vertical Drainage Pipe. Two inch (2") and smaller double sanitary tees may be used for back to back or side by side fixture trap arms without increasing the barrel size.

32. Section 704.3 Commercial Sinks. Delete.

33. Table 703.2 Maximum Unit Loading and Maximum Length of Drainage and Vent Piping. Change fixture unit loading value for one and a half (1 1/2) inch horizontal drainage to two (2) fixture units.

34. Section 705.5.2 Solvent Cement Joints. Add to the end of the section the following: PVC DWV may be joined by the use of one-step solvent cement listed or labeled per U.P.C. Section 301.1.1.

35. Section 707.4 Locations. Add the following: A clean out must be installed for double sanitary tees two (2) inches (50 mm) or less in diameter that receive the discharge from fixture connections. Exception in Section 707.4 does not apply. A full-sized accessible cleanout must be installed in the vertical immediately above the floor or at the base of each waste or soil stack. A full-size cleanout extending to or above finished grade line must be installed at the junction of the building drain and the building sewer. Cleanouts must be installed at fifty (50) foot intervals in horizontal drain lines two (2) inches or smaller.

36. Section 710.3(4) Sewage Ejectors and Pumps. Add: Exception (4): One (1) pump is permitted for "public use" occupancies provided that such tank receives the discharge of not more than one (1) water closet and ten (10) fixture units (See Section 710.9 Alarms).

37. Section 710.5 Size Building Drains and Sewers. Add the following exception: In single family dwellings, one (1) fixture unit may be allowed for each gallon per minute of flow from a pump or a sump ejector.

38. Section 712.1 Media. In the first sentence, delete the phrase "except that plastic pipe must not be tested with air."

39. Section 717.0 Size of Building Sewers. Add the following to the end of section 717.1: Exception: The building drain and building sewer is not less than four (4) inches extending from its connection with the city or private sewer system and must run full size to inside the foundation or building lines.

40. Section 723.0 General. Delete the following sentence: "Plastic DWV piping systems must not be tested by the air test method."

41. Section 801.3.3 Food Handling Fixtures. Add: Food preparation sinks, pot sinks, scullery sinks, dishwashing sinks, silverware sinks, commercial dishwashing machines, silverware-washing machines, steam kettles, potato peelers, ice cream dipper wells, and other similar equipment and fixtures must be indirectly connected to the drainage system by means of an air gap. The piping from the equipment to the receptor must not be smaller than the drain on the unit, but it must not be smaller than one (1) inch (twenty-five and four tenths (25.4) mm).

42. Section 805.41 General. Add to the end of the first paragraph the following: Provisions must be made for the discharge of the water softener to terminate in an approved location. The drain line for a water softener must be three-fourths (3/4) inch minimum. A washer box with a dual outlet is an approved location as long as it is on the same floor or one (1) floor below the softener unit and the water softener drain line is a minimum three-fourths (3/ 4) inch.

43. Section 807.3 Domestic Dishwashing Machines. A domestic dishwashing machine may be installed without the use of an airgap if the drain hose is looped to the bottom side of the countertop and secured properly.

44. Section 906.1 Roof Termination. Add the following:

45. Section 908.1 Vertical Wet Venting. Add to the end of the section the following: A horizontal wet vent may be created provided it is created in a vertical position and all other requirements of Section 908 of the ISPC are met.

46. Section 909.0 Special Venting for Island Fixtures. Add: Parameters for the limited use of Air Admittance Valves (A.A.V.).

47. Section 1002.3 Change of Direction. Trap arms may not exceed one hundred eighty (180) degrees of horizontal turn without the use of a cleanout.

48. Section 1007.0 Trap Seal Protection. Delete section 1007.1 and replace with the following: Floor drains or similar traps directly connected to the drainage system and subject to infrequent use must be protected with a trap seal primer or other approved trap seal protection device, except where not deemed necessary for safety or sanitation by the Authority Having Jurisdiction. Trap seal primers must be accessible for maintenance.

49. Section 1016.1 Discharge. Add the following to the end of section 1016.1: Floor drains installed in residential garages must be permitted to use the interceptor as the fixture trap.

50. Section 1502.1 General. Add to this section the following paragraph: Plumbing for a gray water system from any fixture up to, but not to include the exterior irrigation system tank must be inspected by the Authority Having Jurisdiction. The Idaho Department of Environmental Quality (IDEQ) has jurisdiction to inspect and approve the installation of the exterior irrigation system tank and all piping therefrom to the point of disposal in accordance with IDAPA 58.01.03, "Individual/Subsurface Sewage Disposal Rules." Gray water system location and design criteria requirements related to irrigation and leaching is determined in accordance with the requirements as established by the IDEQ.