Required separation for Title 22 Purple pipe irrigation water and sewer lines

[Captain Jake]

I see a lot of banter about separation of Potable water and sewer lines but I cannot find any data on the following:
If I install a gravity sewer system that takes all of the effluent both liquids and solids from both residential and commercial locations to a wastewater treatment facility that does Title 22 tertiary treatment, can I bring the resulting "Purple Pipe irrigation water" back to the sources in the same trench?
Would it be based on if the wastewater system was a full sewer or just Effluent only wastewater system or would the regulations be the same for both full gravity sewer and effluent only?

 

[Joe.B]

Title 22 of what? When I hear "Title" it's usually referring to a title in the California Code of Regulations, which can be viewed here:

California Code of Regulations - California Code of Regulations

govt.westlaw.com

But CCR Title 22 is Social Security. Did you mean Title 21, or 23, or 24?

 

[Captain Jake]

Title 22 of what? When I hear "Title" it's usually referring to a title in the California Code of Regulations, which can be viewed here:

California Code of Regulations - California Code of Regulations

govt.westlaw.com

But CCR Title 22 is Social Security. Did you mean Title 21, or 23, or 24?

In California's Code of Regulations Title 22, "tertiary water" refers to disinfected tertiary recycled water, a highly treated wastewater that has undergone filtration and a disinfection process to meet stringent public health standards

 

[Gregg Harris]

IPC 1301.1 separation of 5 feet in the same trench, with exceptions

 

[Joe.B]

IPC 1301.1 separation of 5 feet in the same trench, with exceptions

CA doesn't use IPC, we use UPC. Normally they can share a trench as long as you use materials that are approved for use within the building, i.e. glued PVC or ABS. But he's referencing other state laws, so that's why I asked for more detail.

 

[Joe.B]

In California's Code of Regulations Title 22, "tertiary water" refers to disinfected tertiary recycled water, a highly treated wastewater that has undergone filtration and a disinfection process to meet stringent public health standards

Okay, I see it under Division 4, Environmental Health.

 

[Joe.B]

There's a lot in there, I'll poke around a little, but I'm not going to do a deep dive. What I will say though is that in general, CA does a good job of amending model codes to incorporate state laws. Since this appears to come from 2018, I'd say there's a good chance that you can just stick to the CA Plumbing Code as long as you're on private property. Check out 2022 CPC Chapter 15, specifically:

1502.4 Separation Requirements. Underground alternate water source service piping other than gray water shall be separated from the building sewer in accordance with this code. Treated nonpotable water pipes shall be permitted to be run or laid in the same trench as potable water pipes with a 12 inch (305 mm) minimum vertical and horizontal separation where both pipe materials are approved for use within a building. Where horizontal piping materials do not comply with this requirement, the minimum separation shall be increased to 60 inches (1524 mm). The potable water piping shall be installed at an elevation above the treated nonpotable water piping.
Exception: [DWR] Recycled water supply systems that are within or a part of a building shall comply with Section 1505.11.

 

[Captain Jake]

The real issue here has nothing to do with Potable water. I'm being told my our town engineer that we cannot put purple pipe recycle water in the same trench with effluent. All references I can find only call for separation between potable and non potable

 

[Joe.B]

The title of Chapter 15 that I recommended you look at, and of which I cited an appropriate code reference, is titled "Alternate Water Sources for Nonpotable Applications."

The citation I provided tells you that if the sewer piping is constructed out of appropriate materials (basically glued white PVC or black ABS like you would see inside a building) then they can be in the same trench with 12 inches between them. If the sewer pipe is something else, such as clay, AC, or SDR, then the separation required increases to 60 inches.

 

[Captain Jake]

I see the wording but it still gives a distance for treated non potable water with a separation from potable and in the same trench.
I want to know if non potable water that is recycled for irrigation only (this means its non potable), can it be in a trench with untreated effluent

 

[Joe.B]

Ah right, I see what you're saying. That first part of 1502.4 says "shall be separated from building sewer in accordance with this code." So, then you go to 720.0:

720.0 Sewer and Water Pipes.
720.1 General. Building sewers or drainage piping of clay or materials that are not approved for use within a building shall not be run or laid in the same trench as the water pipes unless the following requirements are met:
1. The bottom of the water pipe, at points, shall be not less than 12 inches (305 mm) above the top of the sewer or drain line.
2. The water pipe shall be placed on a solid shelf excavated at one side of the common trench with a clear horizontal distance of not less than 12 inches (305 mm) from the sewer or drain line.
3. Water pipes crossing sewer or drainage piping constructed of clay or materials that are not approved for use within a building shall be laid not less than 12 inches (305 mm) above the sewer or drain pipe.

For the purpose of this section, "within a building" shall mean within the fixed limits of the building foundation.

 

[ICE]

The citation I provided tells you that if the sewer piping is constructed out of appropriate materials (basically glued white PVC or black ABS like you would see inside a building) then they can be in the same trench with 12 inches between them. If the sewer pipe is something else, such as clay, AC, or SDR, then the separation required increases to 60 inches.

If the pipes are approved for use in a building, no separation is required.

 

[Joe.B]

If the pipes are approved for use in a building, no separation is required.

Yup, that is correct, per 720. I was combining the two in my head. The first citation 1502.4 says that his nonpotable water needs to be separated from sewer as required by this code, which sends him to 720. The second part of 1502.4 lists requirements for separation of nonpotable from potable, but it says something very similar to 720, which is why I was mixing the two up.