Flow Meter Installation Question, 6 inches minimum or required. More length?

I just got my flow meter and I am preparing for the installation. I know the installation says to install 6 inches after the backflow. My question is the 6 inches a minimum or the required. My installation would be easier if i could say install it at 7 inches but wanted to get the communities input on if the 6 inches was the exact spot for it to be installed.

@likeabigpizzapie 6 inches is the minimum. Feel free to install at the 7" mark.

Let us know how the install goes and please feel free to ask any questions you might have.


Pictures please!


I hope the photos include a big pizza pie! :pizza:

Here are the pictures as requested. I installed it today. Had an issue with one of the pipes i had got from the store and replaced it with a different pipe and it looks and works great without any leaks.

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I didn’t have a ton of room but installed 4 in PVC around the flow meter to keep dirt and mulch off it. Everything seems to be working great since install about a month ago.


Looks like a nice clean install. If you have room, I may want to get some retaining wall blocks or pavers and build a small sunken down area with gravel / pea shingle in the bottom to allow the signal and better access to flow meter, just a thought. :smile:

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Hello All,

I am looking for clarification on the “6" minimum”. I understand the reason for the dimension, but I would like to know if this is for a piece of pipe only, or can the measurement include a full-port true union ball valve or a regular union both made out of PVC? Thanks.

Hello @GreenLeaf,

My name is Piper and I work on the flow team here at Rachio. First, can you tell me what the pipe size and material of your system are? I am guessing PVC, but is it 1 or 3/4 inch?

Just @ me and I’ll get back to you!



@piperrose 1" PVC

Thank you! The six inches of pipe can include the regular union but not the full-port. The six inches should include as little disruption to the water flow as possible, and sometimes ball valves are mildly disruptive. And I think it’s clear, but just incase, six inches of just pipe with no union is the ideal setup no matter what.


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I have 17 inches available pipe to work on it from the ground to the elbow.
My question is did I’m still able to install flow meter on that 17" pipe.
Please see the picture.

@piperrose @franz Well I never installed the meter when I originally planned on. I am hoping to do it tonight. I wanted to ask again regarding the use of a union. Obviously the inlet & outlet of the meter will be with the 1" PVC-Lock fittings. On the inlet side I would like to add a standard glued PVC union for serviceability. My concern is that I may not have the required 6" of pipe length on the other side of the PVC-Lock fitting to then install the union. So if the union was within the 6" pipe dimension would that adversely affect the readings from the meter? I have limited space (15 - 16") once the vertical pipe passes the bottom of the vinyl siding before it enters the mulch and beyond. I certainly could trench around the pipe and add a sleeve to I could get to the downstream union.
The use of the PVC glued unions at this close location is similar to what you are suggesting for an in-ground install. https://support.rachio.com/hc/en-us/articles/360006370994
Thanks, Dave