Hi Stanky,

I am not from Chicago nor from a winter freezing climate so I can't answer most of your questions. How big is your yard (area)? Will you be putting in plantings as well as grass? Are you doing all the work yourself? Where is the source of water coming from? Will you automate the system? These are general questions that others may wish to know so they can give you more precise answers. IMHO I would not put any water related fixtures inside the house that aren't absolutely needed in the house. They would be just another opportunity for leakage and water damage to occur in your house. If any leakage occurs without you noticing it, the water would attract bug infestations and specifically ground termites. Aloha

Yard is fairly small; about 300 sqft with both grass and plantings. The source of water is fresh water from the main water line inside the house. The system will be automated and I'm planning on doing the work myself.

I assume you are a licensed plumber. To my knowledge you have to be a licensed plumber in Chicago not only to install the backflow and plumbing but you also have to be a licensed plumber to install the sprinkler system.

That being said, it sounds like you are competent in the proper backflow protection and if you feel more comfortable with PVC then go that route. I am in Ohio and most Cities require the Irrigation RPZ to be installed outside while others require indoors. If you do install indoors please run it to a drain. My preference would be outdoors with a union or two depending on local code so it can be removed during the winter. Self draining systems are OK if they are done properly. But rarely are installed properly and over time they can and will fail. But since you plan on purging the system every year you should not have any issues as long as you purge before the weather turns.

Here is a link that might be useful: lawn irrigation watering tips, troubleshooting, product manuals, irrigation blog

ri_ohio, thanks for the follow-up. I would prefer to install the RPZ outdoors and remove as you mentioned.

Do you have a preference between PVC and poly? What do most people use in Ohio?

We work both in Columbus and Cleveland. The further North you get the more Poly you will see. I personally prefer Poly laterals w/ PVC mainline. I repair brittle and damaged PVC every Spring and hardly ever have to repair brittle or damaged Poly. Damage meaning due to freezing temps. I advise you not to use Poly for your mainline if you must then I would recommend a mastervalve.

I am just happy that you are installing the correct backflow device, you have no idea how many improper backflow installs I see and how many systems don't even have them. If you go the Poly route then I would also advise you to use all insert fittings and we always double clamp all the fittings that will receive more pressure: off the valve, 90's, t's and so on. Some will tee into a line with a saddle, we find the saddles to be the number reason for underground leaks besides broken heads. Once we switched from saddles to all insert fittings our call backs dropped in half.

Good Luck..

Here is a link that might be useful: lawn sprinklers