Tie-in Sprinkler System to Main Line

Andy,

There are two issues that I can think of. First you normally need a high pressure pump for the required pressure to drive the sprinkler system and second you should install a one-way valve to ensure the pump will not pump water that's sat in the yard lines back into your home supply lines. That's required by code in most places.

ashroyer wrote:

You will need *some* kind of backflow preventer to protect the municipal supply. Maybe like:

Ask *before* you make any connections.

Jim

When I installed our lawn irrigation system, I installed the required backflow preventer.

Something you might consider is how you will drain the system before hard freezing sets in. In my case, I installed a connection to my air compressor, using a ball valve. When it was time to drain the lines, I merely shut off the water and turned on the air briefly, while cycling the zones.

Mark

A Pump? never heard of one.

Denver area here.

Go to Home Depot or Lowes. They have the necessary anti-siphon valves. If using copper underground be sure to use the proper type for underground use. Flare fittings without solder connections.

I recommend 1 inch PVC for the runs to the valve manifolds. Also include a drain valve at each manifold.

My turn off valve is about 5 feet underground connected directly to the main water line. I didn't put it in and still wonder why they did not put the valve in the basement. Sometimes those valves get hard to turn on and off. They have to be turned on full or the drain valve will weep.

The main turn off valve must be a gate or ball type so as not to lose pressure. They are also available in the sprinkler department of the stores.

Vacuum breaker such as this is required:

I assume you have a basement, since you are talking about breaching your foundation below grade. If so, it is better to route your supply line outside above the foundation. Holes in foundations are rarely a good idea.

First step is to check your water supply for both volume and pressure. If the pressure is too low you will have to put in a pump. You can improve the volume by using a larger supply line.

If you have a basement, you probably have some sillcocks on the house where you hook up your hoses. A good solution would be to replace the line to that sillcock with a larger line, and route it through the original hole, then down to where you will bury your valve box. Around here we put a shutoff and a checkvalve inside (the checkvalve to prevent backflow, but check your codes as they may require an antisiphon valve instead). Then put a new sillcock on the line going down to the valve box; you'll need it occasionally.

I know in areas where it never freezes, they use PVC underground. I've been told that poly is a better choice in areas where there is freezing, as it is more forgiving.

Use more zones, rather than fewer, and since valves are fairly cheap, consider putting in a spare when you build your manifold.

I don't like using an air compressor to blow out the lines, as it takes a rather large compressor and I don't have one, and I won't pay to have mine blown out when, with some foresight, you can put in drains when you are laying the pipe at very little expense, and let the system drain itself. A drain is a cute little device that closes when there is water pressure, but opens when there is no water pressure, so the line drains. Put at least one of these on each zone at the lowest point; I throw in a shovel of gravel to make a little drain field.

My most valuable tip is to f> I am installing a sprinkler system in my yard in Colorado. I am about