View Full Version : irrigation system

ashs inc
11-05-2007, 03:37 PM
Ok guys here you go.....I have a customer that lives on a lake. He just purchased the house and there is a pump running out of the lake to a hose connection. This guy wants to put an irrigation system in and connect it to the pump and also to his city water. HE wants to put a ball valve and be able to turn the city water off and on in case the lake gets low. I need some help on this one guys. thanks in advance.


11-05-2007, 03:55 PM
From your posts here on lawnsite, it doesn't look like you do any irrigation work. At least not anything complicated, right?

Let's call what you wish to do with this lake pump "VERY complicated".

You'll need to have a proper backflow preventer to keep lake water from getting into the house fresh water (potable supply) from the municipal water.

You'll need to prevent the lake pump from coming on when the irrigation system is feeding from the city water. And visa versa. You do not want the irrigation system to get water from both at same time. And you do not want city water backfeeding into the lake.

Of course there are more details.

11-05-2007, 03:59 PM
Stop and back the truck up. Before you do anything check with the city to see what restrictions there are with mixing lake and city water systems. There is a very good chance it will not be allowed regardless of how you set it up.

Now you can use the lake water for irrigation, assuming that is allowed. All kinds of funny water use restrictions came about this year in the south.

Long story short -> check to see what is allowed, then proceed to step 2.

P.S. If WalkGood is correct about experience level, refer the job to someone who is qualified.

Mike Leary
11-05-2007, 06:59 PM
We've pulled this off by doing the following: provide air gap ABOVE the pond
overflow & with 24-volt valve with float add potable..our purveyor permitted
it with a DCVA, tho RPBAs are becoming the norm.

11-06-2007, 12:24 AM
Don't expect a lake-water/city water interconnection without an RPZ in the city water side. Even if some official decides you can get by with less, don't design a system without the RPZ

These types of interconnects can get towns seeing red, and the level of possible official nastiness can go right off the charts.

ashs inc
11-06-2007, 11:12 AM
thanks for the help guys. I told this guy that i didnt think it was a good idea.

Mike Leary
11-06-2007, 05:11 PM
thanks for the help guys. I told this guy that i didnt think it was a good idea.

It's a great idea, it just takes a pro & $$$$.:)

11-06-2007, 08:14 PM
have a couple of houses with similar setups, they work great, you just have to do it correctly. this can be done cheaply via manual valves or expensively being automatic...

11-07-2007, 09:35 AM
Here is what you should tell him. Get a well dug and have that feed the pond with a backflow preventor and all the proper hoopla. Get a float switch in the pond connected to the well so that when the lake gets low the well pump kicks on and brings it back to a proper level. Keep the irrigation coming off the pond with a filter step up to reduce the crap intake. We have the same set up on a couple commerical deals we have works like a charm and the town gave the thumbs up.

AI Inc
12-18-2007, 03:44 PM
Anytime I did them we didnt connect the system to the backflow. Just had it there for future use as the plumbing inspector would have had a coniption.
How much does water in your area cost? Lake water isnt the wonderful thing people think it is. It will double maitanance costs and cut the life of the system.
As I told 1 customer that wanted it " its like buying a mercedes and then putting used motor oil into the gas tank to save on fuel costs"