Do Auto-filler Float Valves have Backflow Preventers?

[LynnOnTheWeb]

Our house has a rainwater collection system that supplies all the water to the house. We use municipal water for the sprinkler system, but currently it's on the house's rain water.

To do this we need to cut one of the pipes that currently supplies the water to the pool for the auto-filler. We have a raised pool with a vanishing edge and this is the pipe to the autofiller in the overflow basin. The water supply is about 2' off ground level and the filler is about 7' from ground level.

If we cut this pipe, is water going to be draining out of the pool? Let’s assume we are keeping the float high enough to not be open/filling during this process.

Our other option is to install it near the PVB where we have multiple valves we can turn off to isolate a section of the pipe.

 

[mas985]

If we cut this pipe, is water going to be draining out of the pool?

Auto-fillers generally do not come with a check valve or anti-siphon device but do you know if someone installed one between the two locations which is normally done?

If not, and the cut is below the pool water level, then it will drain out to that level.

 

[JoyfulNoise]

Are you using the rainwater system as potable water in your home or just as grey water for flushing toilets and such?

If the rainwater system is being used to generate potable water for food prep and drinking, then you need to be really careful about isolating the supply lines from other uses. Pool water is not sanitary and the rainwater tank should never be exposed to any positive back flow from the pool. Gravity isn't enough, you need to make sure there is positive isolation usually in the form of a double check-valve back flow preventer (Zurn Wilkens or Watts). The back flow prevent will have built-in ball vales for isolation as well as pressure test points. It's important to have these types of valves checked annual for proper operation as you are dealing with potentially hazardous conditions if a failure occurs.

 

[LynnOnTheWeb]

Yes the collection tank is also potable water. It's used for everything in the house.

This is currently how it's connected. That hose bib comes from the rainwater tank. We want to change the water source to the water supplied by the meter and come off of the main line/pipe from the sprinkler.

 

[JoyfulNoise]

Please mark the picture with the sources listed - city water line, rain water line, and irrigation line. Also mark where that flex line is going. I think I know which is which but it’s confusing. You’re also going to have to remove that insulation foam so we can see what’s on these pipes and what they are made of. My guess is you have a mix of PVC, copper, and galvanized pipe. You may need to pay a plumber to come in and do the work unless you’re handy with a MAP gas torch and copper brazing techniques.

 

[LynnOnTheWeb]

I shot some videos this morning to help explain everything. We aren't working with copper on this and I'm pretty handy.

Here's the pool from the top showing where the auto-filler float valve (toilet type) is and the locations of the photos I took yesterday:

Here are more details from below about the setup and what I want to do:

Thanks for taking a look.

 

[JamesW]

An autofill is usually required to have an antisiphon and anti-backflow valve.

You have a complicated system and you probably need to have a plumber come onsite to review everything and advise you about what's what.

 

[JamesW]

SECTION 608 PROTECTION OF POTABLE WATER SUPPLY

608.1 General.

A potable water supply system shall be designed, installed and maintained in such a manner so as to prevent contamination from non-potable liquids, solids or gases being introduced into the potable water supply through cross-connections or any other piping connections to the system.

Backflow preventers shall conform to the applicable Standard referenced in Table 608.1.

Backflow preventer applications shall conform to Table 608.1, except as specifically stated in Sections 608.2 through 608.16.27 and Sections 608.18 through 608.18.2.

https://ldh.la.gov/assets/oph/Center-EH/engineering/CCC/2015_IPC_CCC_Requirements_Amended.pdf

 

[JamesW]

What are some examples of cross-connections?

A swimming pool auto fill line

A landscape sprinkler or drip system

A decorative fountain that has an auto fill line

A hose bib or any outlet that will accommodate the attachment of a hose

Most fire sprinkler systems

Plumbing connected equipment or apparatus

Who is required to have a backflow prevention assembly?

Any water customer with a cross-connection is required to install appropriate backflow protection.

Federal and State laws require that water suppliers protect their water systems from contamination by requiring the installation and testing of appropriate backflow assemblies.

Commercial and industrial customers and homes with dedicated landscape meters are required by City Ordinance and State Administrative Code rule R18-4-215 to install, test, and maintain backflow prevention assemblies.

In addition, the City of Mesa has adopted the 2006 International Plumbing Code.

This code specifies backflow requirements for water customers including all single family residences.

Backflow FAQ | City of Mesa

Backflow FAQ

www.mesaaz.gov

 

[JoyfulNoise]

OK, watched the videos several times and ... WOW ... your water life is complicated (coming from the guy that lives in the desert).

To answer your question ... yes, you can use the irrigation supply line closest to the pool to supply water to the autofill pot ... BUT ... you must use a double check valve back flow preventer like what is on the wall currently by your hose bib connection. So it's a question of complication versus resusing what you have. You can either tie in the line that runs near your equipment pad to that back flow preventer or you can move the whole setup to the wall under the pool or you can simply deprecate what you have by the hose bib (shut off valves and cap off lines) and install a complete new setup on the wall by the pool.

The trick is that your pool is raised ABOVE the level of the feed water so you absolutely need that back flow preventer AND enough supply pressure to keep pool water from flowing into your irrigation line OR being siphoned into the irrigation line.

If it were me, I would not reuse old stuff. I would want a new installation of a double check valve back flow preventer and anti-siphon valve as well as a pressure regulator if the supply pressure is not already regulated.

Do you know if the irrigation line that was just laid out is going to be at the municipal system pressure OR is there a regulator on it?

Also, be very careful with irrigation systems - sometimes people install filters on the lines that are capable of holding fertilizer cartridges so they can create irrigation water will fertilizer nutrients in it ... you don't want that in your pool.

Also realize that irrigation water is going to come with all the possible chemistry downsides of municipal water that rain water does not have - high mineral hardness, carbonate alkalinity, high pH. This is going to affect your pool water chemistry a lot.

 

[JoyfulNoise]

One other thought is to have both options available for the pool - keep what you have that uses your rain water system AND install another supply that uses the irrigation system. Then simply use the water supply that makes the most sense in the moment - rain water when the harvesting tank is full and muni water when the summer dry season heats up.

But again, the lines will all need back flow/anti-siphon setups AND you should really have them tested annually to ensure they are working.

 

[mas985]

I think you may be identifing the wrong pipes:



I believe the autofill is the upper pipe and the lower one is perhaps for the for the catch basin drain although it looks smaller than it should be. Before cutting anything you may want verify these lines.

If the autofill line you showed in the first video at the house is after the anti-siphon valve, then I would cut the line before the anti-siphon and plumb in the municipal water there.

 

[JoyfulNoise]

One of them could also be the fill pot overflow line. If it’s an open pipe drain somewhere then the fill pot overflow may have been plumbed in. My fill pot overflow is not plumbed but sealed. Easy enough to check.

 

[mas985]

I thought of that as well but normally, they are on the same side of the pot close together so why didn't they just run them together? The one at the bottom of the catch basin is odd. There should be a large drain pipe for the pump but I don't see one other than the smaller pipe. But that could be a separate overflow if there is a standpipe in the middle of the basin. Maybe a picture of the catch basin right above the lower pipe would give us a clue.

 

[JamesW]

Can you show the main drains in the trench and all holes in the trench for water to go in or out?

Can you show the float valve autofill mechanism?

What is the make and model of the float valve autofill mechanism?

The supply needs to go before the backflow preventer/antisiphon valve for the autofill.

You have cutoff valves, so it should not be a problem.

The irrigation needs to also have a backflow preventer/antisiphon valve.

Do you have a plumber that you work with?

If yes, are they confused on what to do?

If no, do you have a plumber that you can consult with to help you do this correctly and to local code?