Iowa Code r. 481-425.4 - Amendments to Uniform Plumbing Code

The UPC, as adopted by reference in rule 481-425.1(105), is amended as follows:

(1) The following amendment apply to UPC Chapter 1: Section 101.2 Scope. Modify the section by adding the following sentence to the end of the section: "Local jurisdictions may administer the permit, inspection, testing, and enforcement provisions contained in this code. Permit, inspection, testing, and enforcement provisions contained in this code are not administered by the Plumbing and Mechanical Systems Board or the state."

(2) The following amendments shall apply to UPC Chapter 3:

a. Section 301.5 Alternative Engineered Design. Modify the section by adding the following sentence to the end of the section: "No engineered single-stack drainage system shall be installed."

b. Section 309.6 Dead Legs. Modify the section by adding the following sentence to the end of the section: "The authority having jurisdiction can determine the method of flushing."

c. Subsection 314.4.1 Installation of Thermoplastic Pipe and Fittings. Trench width for thermoplastic pipe shall be limited to six times the outside diameter of the piping at the base and thermoplastic piping be bedded in not less than 4 inches (102 mm) of aggregate bedding material supporting the pipe. Initial backfill shall encompass the pipe, and aggregate material shall be three-eighths (3/8) inch p-gravel or 1-inch clean class one bedding.

(3) The following amendments shall apply to UPC Chapter 4:

a. Section 402.5 Setting. Modify the section by adding the following sentence to the end of the section that begins "Exception:": The installation of paper dispensers, sanitary napkin disposal unit or accessibility grab bars shall not be considered obstructions.

b. Section 407.3 Limitation of Hot Water Temperature for Public Lavatories. Modify the section by adding the following sentence to the end of the section: "These devices shall be installed at or as close as possible to the point of use."

c. Section 408.12 Showers. Create a new Section 408.12 stating: "Limitation of Hot Water Temperature of Pet Grooming Stations. The maximum hot water temperature discharging from pet grooming stations shall be limited to 120ºF (49ºC) and the maximum temperature regulated by one of the following means, which shall be installed at or as close as possible to the point of use:

"(1) A limiting device conforming to ASSE1070, ASMEA112.1070, CSAB125.70, or CSAB125.3.

"(2) A water heater conforming to ASSE 1084."

d. Section 409.4 Limitation of Hot Water in Bathtubs and Whirlpool Bathtubs. Modify the section by adding the following sentence to the end of the section: "These devices shall be installed at or as close as possible to the point of use."

e. Section 410.3 Limitation of Water Temperature in Bidets. Modify the section by adding the following sentence to the end of the section: "These devices shall be installed at or as close as possible to the point of use."

f. Section 416.5 Drain. Modify the section by deleting the last sentence, which states: "Where a drain is provided, the discharge shall be in accordance with Section 811.0."

g. Section 418.3 Location of Floor Drains. Modify the section by adding the following to the end of the section: "(5) Rooms equipped with a water heater."

h. Section 422.1 Fixture Count.

Modify the section by deleting the first paragraph and inserting the following in lieu thereof: "Plumbing fixtures shall be provided in each building for the type of building occupancy and in the minimum number shown in Table 403.1 of the International Plumbing Code, reprinted here as Table 422.1. The design occupant load and occupancy classification shall be determined in accordance with the state building code or the authority having jurisdiction. Required public facilities shall be designated by a legible sign for each sex and signs be readily visible and located near the entrance to each toilet facility."

i. Table 422.1 Minimum Plumbing Facilities. Delete the table and insert the following table in lieu thereof.

TABLE 422.1 MINIMUM NUMBER OF REQUIRED PLUMBING FIXTURESa (See Sections 403.1.1 and 403.2) (Reprinted with permission,* from the 2018 International Plumbing Code, excerpt from IPC Table 403.1)
NO.	CLASSIFICATION	DESCRIPTION	WATER CLOSETS (URINALS: SEE SECTION 422.7)		LAVATORIES		BATHTUBS/ SHOWERS	DRINKING FOUNTAIN (SEE SECTION 415.0)	OTHER
			MALE	FEMALE	MALE	FEMALE
1	Assembly	Theaters and other buildings for the performing arts and motion picturesd	1 per 125	1 per 65	1 per 200		-	1 per 500	1 service sink
		Nightclubs, bars, taverns, dance halls and buildings for similar purposesd	1 per 40	1 per 40	1 per 75		-	1 per 500	1 service sink
		Restaurants, banquet halls and food courtsd	1 per 75	1 per 75	1 per 200		-	1 per 500	1 service sink
		Gaming areas	1 per 100 for the first 400 and 1 per 250 for the remainder exceeding 400	1 per 50 for the first 400 and 1 per 150 for the remainder exceeding 400	1 per 250 for the first 750 and 1 per 500 for the remainder exceeding 750		-	1 per 1,000	1 service sink
		Auditoriums without permanent seating, art galleries, exhibition halls, museums, lecture halls, libraries, arcades and gymnasiumsd	1 per 125	1 per 65	1 per 200		-	1 per 500	1 service sink
		Passenger terminals and transportation facilitiesd	1 per 500	1 per 500	1 per 750		-	1 per 1,000	1 service sink
		Places of worship and other religious servicesd	1 per 150	1 per 75	1 per 200		-	1 per 1,000	1 service sink
		Coliseums, arenas, skating rinks, pools and tennis courts for indoor sporting events and activities	1 per 75 for the first 1,500 and 1 per 120 for the remainder exceeding 1,500	1 per 40 for the first 1,520 and 1 per 60 for the remainder exceeding 1,520	1 per 200	1 per 150	-	1 per 1,000	1 service sink
		Stadiums, amusement parks, bleachers and grandstands for outdoor sporting events and activities	1 per 75 for the first 1,500 and 1 per 120 for the remainder exceeding 1,500	1 per 40 for the first 1,520 and 1 per 60 for the remainder exceeding 1,520	1 per 200	1 per 150	-	1 per 1,000	1 service sink
2	Business	Buildings for the transaction of business, professional services, other services involving merchandise, office buildings, banks, light industrial and similar uses	1 per 25 for the first 50 and 1 per 50 for the remainder exceeding 50		1 per 40 for the first 80 and 1 per 80 for the remainder exceeding 80		-	1 per 100	1 service sinke
3	Educational	Educational facilities	1 per 50		1 per 50		-	1 per 100	1 service sink
4	Factory and Industrial	Structures in which occupants are engaged in work fabricating, assembly or processing of products or materials	1 per 100		1 per 100		-	1 per 400	1 service sink
5	Institutional	Custodial care facilities	1 per 10		1 per 10		1 per 8	1 per 100	1 service sink
		Medical care recipients in hospitals and nursing homes	1 per roomc		1 per roomc		1 per roomc	1 per 100	1 service sink
		Employees in hospitals and nursing homesb	1 per 25		1 per 35		-	1 per 100
		Visitors in hospitals and nursing homes	1 per 75		1 per 100		-	1 per 100
		Prisonsb	1 per cell		1 per cell		1 per 15	1 per 100	1 service sink
		Reformatories, detention centers, and correctional centersb	1 per 15		1 per 15		1 per 15	1 per 100	1 service sink
		Employees in reformatories, detention centers and correctional centersb	1 per 25		1 per 35		-	1 per 100	-
		Adult day care and child day care	1 per 15		1 per 15		1	1 per 100	1 service sink
6	Mercantile	Retail stores, service stations, shops, salesrooms, markets and shopping centers	1 per 500		1 per 750		-	1 per 1,000	1 service sinke
7	Residential	Hotels, motels, boarding houses (transient)	1 per sleeping unit		1 per sleeping unit		1 per sleeping unit	-	1 service sink
		Dormitories, fraternities, sororities and boarding houses (not transient)	1 per 10		1 per 10		1 per 8	1 per 100	1 service sink
		Apartment house	1 per dwelling unit		1 per dwelling unit		1 per dwelling unit	-	1 kitchen sink per dwelling unit; 1 automatic clothes washer connection per 20 dwelling units
		Congregate living facilities with 16 or fewer persons	1 per 10		1 per 10		1 per 8	1 per 100	1 service sink
		One- and two-family dwellings and lodging houses with five or fewer guestrooms	1 per dwelling unit		1 per dwelling unit		1 per dwelling unit		1 kitchen sink per dwelling unit; 1 automatic clothes washer connection per dwelling unit
		Congregate living facilities with 16 or fewer persons	1 per 10		1 per 10		1 per 8	1 per 100	1 service sink
8	Storage	Structures for the storage of goods, warehouses, storehouse and freight depots. Low and Moderate Hazard.	1 per 100		1 per 100		-	1 per 1,000	1 service sink

^a The fixtures shown are based on one fixture being the minimum required for the number of persons indicated or any fraction of the number of persons indicated. The number of occupants shall be determined by the International Building Code.

^b Toilet facilities for employees shall be separate from facilities for inmates or care recipients.

^c A single-occupant toilet room with one water closet and one lavatory serving not more than two adjacent patient sleeping units shall be permitted provided that each patient sleeping unit has direct access to the toilet room and provision for privacy for the toilet room user is provided.

^d The occupant load for seasonal outdoor seating and entertainment areas shall be included when determining the minimum number of facilities required.

^e For business and mercantile classifications with an occupant load of 15 or fewer, service sinks will not be required.

^* Excerpted (with modifications) from Table 403.1 of the 2018 International Plumbing Code; Copyright 2017; Washington, D.C.: ICC. Reproduced with permission. All rights reserved. www.ICCSAFE.org

j. Insert the following text at the end of Chapter 4:

"422. 8 Substitution for Water Closets. In each bathroom or toilet room, urinals shall not be substituted for more than 67 percent of the required water closets in assembly and educational occupancies and not be substituted for more than 50 percent of the required water closets in all other occupancies. (Reprinted from the 2021 International Plumbing Code section 424.2)"

(4) The following amendments shall apply to UPC Chapter 6:

a. Section 603.4.8 Drain Lines. Modify the section by adding the following language to the end of the last sentence in the section: "or in accordance with the manufacturer's drain-sizing chart for installation."

b. Section 609.1 Installation. Insert the following: "Building supply yard piping shall be not less than 60 inches below earth cover."

c. Section 609.12 Pipe Insulation. Delete Sections 609.12 through 609.12.2 and insert the following in lieu thereof:

"Section 609.12 Pipe Insulation. Insulation of domestic hot water piping shall be in accordance with the state applicable energy conservation code."

d. Section 611.4 Sizing of Residential Softeners. Modify the section by adding the following to the end of the last sentence in the section: "or as specified in the manufacturer's installation instructions."

e. Section 612 Residential Fire Sprinkler Systems. Delete sections 612.0 through 612.7.2.

(5) The following amendments shall apply to UPC Chapter 7:

a. Section 702.1 Trap Size. Table 702.1 Note 9. Modify this note by deleting "a maximum shower size of 36 inches (914 mm) in width and 60 inches (1524 mm) in length" and inserting the following in lieu thereof: "showers having only one shower head rated at a maximum of 2.5 gpm."

b. Section 710.1 Backflow Protection. Modify the section by adding the following sentences to the end of the section: "The requirement for the installation of a backwater valve shall apply only when determined necessary by the Authority Having Jurisdiction based on local conditions. When a valve is required by the Authority Having Jurisdiction, it will be a manually operated gate valve or fullway ball valve. An automatic backwater valve may also be installed but is not required."

(6) The following amendments shall apply to UPC Chapter 8:

a. Section 807.3 Domestic Dishwashing Machine. Modify the section by deleting the section and inserting the following language in lieu thereof: "No domestic dishwashing machine shall be directly connected to a drainage system or food waste disposer without the use of an approved dishwasher air gap fitting on the discharge side of the dishwashing machine, or by looping the discharge line of the dishwasher as high as possible near the flood level of the kitchen sink where the waste disposer is connected. Listed air gap fittings shall be installed with the flood level (FL) marking at or above the flood level of the sink or drainboard, whichever is higher."

b. Section 814.5 Point of Discharge. Delete Section 814.5 and insert the following in lieu thereof:

"Section 814.5 Point of Discharge. Air-conditioning condensate waste pipes shall connect indirectly to a properly trapped fixture, floor drain, or open sight drain, or where permitted in Section 814.6, to the drainage system through an air gap or air break to trapped and vented receptors, dry wells, leach pits, sump pump, the tailpiece of plumbing fixtures or indirectly to the building storm sewer through a roof drain. A condensate drain shall be trapped in accordance with appliance manufacturer's instructions or as approved."

(7) The following amendments shall apply to UPC Chapter 9:

a. Section 901.1 Applicability. Modify the section by adding the following sentence to the end of the section: "No engineered single-stack drainage systems shall be installed."

b. Section 906.1 Roof Termination. Modify the section by deleting the last sentence.

c. Section 908.2.2 Size. Delete the second sentence in this section and insert the following new sentence in lieu thereof: "The wet vent shall be not less than 2 inches (50 mm) in diameter for 6 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 7 dfu or more."

(8) The following amendments shall apply to UPC Chapter 10:

a. Table 1002.2 Horizontal Lengths of Trap Arms. Delete the table and insert the following table in lieu there of:

TABLE 1002.2 Horizontal Lengths of Trap Arms (Except for Water Closets and Similar Features)1,2
Trap Arm Diameter (inches)	Distance Trap to Vent Minimum (inches)	Length Maximum (feet)
11/4	21/2	5
11/2	3	6
2	4	8
3	6	12
4	8	12
Exceeding 4	2 × Diameter	12

For SI units: 1 inch = 25.4 mm Notes:

¹Maintain 1/4 inch per foot slope (20.8 mm/m).

²The developed length between the trap of a water closet or similar fixture (measured from the top of the closet flange to the inner edge of the vent) and its vent shall not exceed 6 feet (1829 mm).

b. Section 1014.1.3 Food Waste Disposers and Dishwashers. Modify the section by deleting the second sentence and inserting the following in lieu thereof: "Commercial food waste disposers shall discharge into the building's drainage system in accordance with the requirements of the Authority Having Jurisdiction."

(9) The following amendments shall apply to UPC Chapter 12:

a. Sections 1205.0 through 1205.2 Authority to Render Gas Service. Delete the sections.

b. Sections 1207.0 and 1207.1 Temporary Use of Gas. Delete the sections.

c. Subsection 1208.5.3.5 Corrugated Stainless Steel Tubing. Delete subsection 1208.5.3.5 and insert the following in lieu thereof:

Subsection 1208.5.3.5 Corrugated Stainless Steel Tubing. Only CSST with an arc-resistant jacket or covering system listed in accordance with ANSI LC-1 (Optional Section 5.16)/CSA 6.26-2016 shall be installed, in accordance with the terms of its approval, the conditions of listing, the manufacturer's instructions and this code, including electrical bonding requirements in Section 1211.2. CSST shall not be used for through-wall penetrations from the point of delivery of the gas supply to the inside of the structure and not be installed in locations where subject to physical damage unless protected in an approved manner.

d. Section 1211.3 Arc-Resistant Jacketed CSST. Delete the section.

(10) The following amendment shall apply to UPC Chapter 13:

Section 1306.3 Report Items. Modify the section by deleting "Authority Having Jurisdiction" and inserting "responsible facility authority" in lieu thereof.

Notes

Iowa Code r. 481-425.4

ARC 8913C, IAB 2/19/2025, effective 3/26/2025; Editorial change: IAC Supplement 4/2/2025