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These instructions presume that this work is being done in a mild climate where water meters are normally installed in the yard by the street- where the hookup is performed by digging and installing fittings in direct contact with the soil. In colder climates, the meter may be located in the basement, eliminating the need to dig in order to access the meter connections. It should be clear how to modify these directions to accomplish a connection in a colder climate- just ignore all the digging! Also, the large PVC pipe referred to may actually be metal, and may require cutting and sweating fittings with a propane torch and lead free solder. As you read the instructions on this page, refer to the picture below.
Dig up the water line
Dig up the water line from the outlet of the meter all the way to and including about a foot of the PVC line to the house. This may involve digging up several feet of line. Dig a few inches under the line to allow a place for water to drain without putting the line in a mud puddle, and to allow for some movement of the line in all directions. Be careful, of course, not to damage the line while exposing it. As you are digging, decide where you want to place the backflow preventer and dig out an area long, wide and deep enough to accomodate the backflow preventer and it's box. Normally, the backflow preventer must be located on your property, not in the setback which may extend several feet into "your" lawn. The edge of your property is often marked by the first expansion joint in the driveway.
How to disconnect the water line
First, shut off the water to the meter using the angle valve on the street side of the meter. The easiest place to disconnect the main line to your house is on the outlet (downstream side) of the meter. The meter is installed with a special fitting called a meter nip ple, which is attached by way of a nut that rotates independent of the pipe itself. The nut can be unscrewed, allowing the pipe to simply be pulled to the side. After loosening the nut, each of the threaded joints around the shut-off valve and PRV can be unscrewed. Use large adjustable wrenches on the meter nut, and a pipe wrench on the pipe itself.
Installing the new tee
After the meter nut is loosened, unscrew the joint where you want to insert the threaded tee. This may require digging up enough room to swing the shut-off valve through a full circle if you are removing a pipe with the valve attached. We recommend adding the tee to the outlet (downstream side) of the shut-off valve. Wrap both ends of a short threaded nip ple with several layers of Teflon tape. Also wrap the end of any threaded pipe ends which you removed up to this point. Screw the nip ple into the outlet of the shut-off valve, then screw the new threaded tee onto the short nip ple. The other end of the new tee should now be screwed into the original pipe.
A note about water pressure
Note: If you have unusually high pressure you may have a PRV installed after the shut-off valve. You can install the sprinkler system downstream of the PRV if you want to take advantage of the regulated pressure, but this will probably result in noticeable drop in water pressure while watering. This may not be a problem if all watering is done at night while everyone is asleep. If you install the system between the shut-off valve and the PRV, you won't see much (if any) effect on house water pressure during watering, but you will definitely need to to provide for pressure or flow control (for instance by installing a master valve with flow control). If you have no PRV, then you probably have moderate to low pressure and flow controls may not be critical, although they are important to obtain good pressure balance as explained in the section on adjusting your sprinkler system.
Remove a section of water line
By now, you will probably notice that the waterline is so long that you have to shorten it in order to fit it back on the meter. In fact, you may not be able to reassemble it without cutting it somewhere to take out some extra length. Carefully measure how much extra length you added to the water line, and remove this much (plus about 1/8 inch) from the large PVC pipe running to the house. This will give you just enough room to re-install the removed section of pipe and a repair coupling. Make sure all threaded joints are taped, tight, and the new tee is pointed in more or less the right direction to go to the backflow preventer. Deburr the cut in the large PVC pipe and install a coupling to repair the cut. QUICKLY, BEFORE THE COUPLING DRIES, reattach the meter nip ple to the meter using the meter nut so that the coupling dries to just the right length to fit.
Pat yourself on the back
At this point, you will have done the hardest part of the backflow preventer installation. Congratulations!
Connecting your backflow preventer
Tape a male adapter with Teflon tape and screw it into the new tee. By using two ells as described in the Tips and Tricks section on "funny angles", you can arrange for a pipe to head toward your sprinkler shut-off valve and backflow preventer at just about any angle. A couple more ells may be required at the sprinkler shut-off valve and backflow preventer to establish the right height and angle for those devices as well. Remember to observe the code requirements for depth of cover for the pipe between the supply line and the backflow preventer.
Mounting your backflow preventer
Be sure to check on clerances for mounting the backflow preventer. If it is above ground there will be minimum clearances above grade or the highest sprinkler. If it is below ground (a DCA) there may be restrictions on the distance from the DCA to the bottom of the box enclosure, to the top, as well as for the orientation of the test and repair ports (up). If there are restrictions, your building permit office or water utility should be able to explain them to you.
Install the master valve
If you chose to install a master valve (a good move) it goes after the backflow preventer and should be located close to the backflow preventer. After the master valve is installed, it's time to start laying the main line, station valves, lateral lines and sprinklers.
How to make a compression fit connection
Back to main backflow instruction page
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