Plumbing Fixtures in the 2022 Codes by Kerwin Lee, AIA

In California the requirements for plumbing fixture counts are contained in the California Plumbing Code (CPC), not in Chapter 29 of the Building Code, as they are in the states which adopt the International Building Code (IBC). This article will address only CPC, which is based on the 2021 Uniform Plumbing Code (UPC) written by the International Association of Plumbing & Mechanical Officials (IAPMO). The reason and history of this goes back to what is called the legacy codes, codes before the International Code Council (ICC) set of Codes we use today. The history of this is another story for another time.

What has prompted this article are changes in the 2022 CPC with the elimination of Table A, Occupant Load Factor for determining fixture counts. This table was only adopted and enforced by the Division of the State Architect (DSA). Before we go into the current change, let’s look at what the code says on how to determine fixture counts for a building. 

Determining toilet fixture requirements has always been challenging and an exercise in creative accounting. What needs to be understood is what the code requires (if anything). Under the California Building Code (CBC), Chapter 29 is not adopted or used and will point you to the California Plumbing Code (CPC). In the CPC we have Chapter 4, Section 4.22 for determining the minimum number of fixtures for a given use. This section says to use the Occupant Load Factors from the Building Code, Section 1004 for egress and Table 1004.5/Occupant load factors. Once you determine the occupant load, which is a task in itself, you go back to the CPC Table 4.22-1 for the minimum number of required fixtures for a given use. This is what I see as the basic requirement from the code. 

You will see in the CPC that there are Tables 4-1/Occupant load factors and Tables 4-2, 4-3 and 4-4 for fixture counts. So,do we have to use these other tables? In the great state of confusion (California), the CBC has adoption matrices. These matrices tell who has adopted or amended a section and who enforces the section. One has to understand which agency within this state has jurisdiction over a specific type of project to apply the correct section of the code. If you look at the adoption matrix for Table 4-1 of the CPC, you will find that the following agencies have adopted or amended this Table or chapter or portions of the chapter: • Building Standards Commission (BSC), State building and UC buildings.• Division of the State Architect/Access Compliance (DSA/SS), State buildings and public schools. For Table 4-2 the enforcing agency is Office of State Health Planning and Development (OSHPD), Medical facilities • Department of Consumer Affairs (CA) Barber shops, schools of cosmetology and electrology, acupuncture offices, pharmacies, veterinary facilities and structural pest control. Table 4-3 is under the Department of Agriculture and Table 4-4 under the Department of Public Health.

If the project you are working on is not on the list above of enforcing agencies, Chapter 4 and Table 4-1 of the CPC are not applicable and not enforced by the State. This is where the omission by the State of the plumbing fixture tables from Chapter 29 in the IBC compounds the confusion. If the designer does not use Table 4-1 the California Code leaves them with no alternative for reference. You can look at the plumbing fixture table in Chapter 29 of the CBC, but its use will be subject to negotiation with the AHJ. It is possible that a local jurisdiction will adopt Table 4-1 or other requirements to be enforced within a local jurisdiction. This would have to be done through a local ordinance specifically adopting the Chapter to be enforced by the local building official. Check with the local Authority Having Jurisdiction (AHJ) to see if there is a specific adoption of Chapter 4, Table 4-1 of the CPC. 

In my opinion the tables are neither correct or wrong, but really a guideline. The table in the UPC/CPC has changed very little over the past 30+ years. The table is a simplified approach to determining the number of fixtures. The assumption is that the calculated occupant values, using any of the Table factors, are divided by a 50% split for male and females within any given building or floor. If this basic assumption is wrong, everything else is incorrect. The table does not reflect what has been called potty parity. State law has tried to correct this and factor in that women need more fixtures. The Table in Chapter 29 of IBC more accurately reflects this potty parity. Impact loading is a key element in how facilities are used. A normal office building never has the facilities full unless there is an impact load. This would be from a group leaving a meeting or scheduled employee break. The impact loading mainly applies to assembly uses, where halftime or the seventh inning stretch at a sporting event, or an intermission at a theater, create large impact loads that are not adequately addressed by the table. The impact load at a movie theater is different from one at a formal theater event. A formal event would require even more time to filter through the facilities based on the amount of clothes one wears. Toilet fixture count should be based on a timed use factor. How long is one willing to wait to use the facilities? What is an acceptable wait? This is a convenience issue. 

Most Authorities Having Jurisdiction (AHJ) are flexible regarding what compliance is. They will probably allow flexibility in the tabulation of the occupant load. What should be presented by the design professional is a reasonable approach based on the requirements found in either the UPC/CPC or the IBC/CBC. Any major deviation should be based on the anticipated use and the approval of both the AHJ and the owner/operator of the facility. 

Back to the original issue, the deletion Table A is noted in the first printing of the 2022 (CPC) California Codes. There is rumor that it may be coming back in a supplement. In any case, this table was and will continue to only be adopted and enforced by DSA and applies to their projects. 

Add to all of this family use, unisex, accessible toilet facilities and gender neutral requirements, how do you add or subtract these into the total count? It is not an easy task to understand and comply with what the code is asking for.

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  1. Hi Kerwin Lee,
    Your article is very helpful. The only part that I question is that if the BSC adopts Table 4-1, then doesn’t that mean that all local jurisdictions would adopt it with the rest of the code unless there is a local ordinance? Why would it be any different from the rest of the building code? It’s not like there is a box in the matrices for each local agency to check off, or am I missing something? -Thank you.