Sketch your property to scale on one or multiple pieces of graph paper. Take accurate measurements with a tape measure and sketch in all landscape features including the house, flower beds, vegetable gardens, trees, shrubs, fences, the water meter, and any other major feature of your yard. If you are planning to add features, but they do not exist yet, add these to the plan, or add them to the landscape before installing the irrigation system. Draw a dotted line where the trenches need to be dug and place a black dot indicating the location of each sprinkler head. Place enough heads to provide each area with double water coverage. Also, plan where you will install the valve boxes (one valve per station).
Plan the locations of each watering station. Each station should consist of 6 to 10 sprinkler heads, depending on the amount of water pressure you have available. Test your water pressure with a water pressure gauge before moving on.
Take your plan to a home improvement store to purchase all of the components at the same time. Large purchases may qualify for a discount.
Dig all of the trenches with a trenching shovel. The trenches that will have multiple supply lines running through them will need to be dug very deep to keep the pipes below the frost line in your area. Mark the locations of each sprinkler head with a marking flag.
Tap into the main water supply line (whether this is a culinary water supply line or a secondary, gray, water supply line) somewhere near the water meter by using what is called a compression tee. This connector will prevent the need to solder into a copper water main, or thread onto a galvanized main water supply line, depending on what kind of material the water main is made of.
Begin running main water supply PVC pipe for each valve manifold box that will be required to run each watering station. Connect each pipe with the appropriate fittings according to the overall installation plan by gluing them together with PVC primer and adhesive. The primer cleans the PVC surfaces of the PVC pipe while the adhesive provides a tight bond. Apply PVC primer to the end of the PVC pipe and then to the inside surface of the PVC fitting. The primer will dry quickly. Then apply a generous amount of PVC adhesive to the primed surfaces. Slip the fitting onto the end of the pipe, twist the fitting into its final position, and allow the joint to dry. Wipe away any excess adhesive with a cloth rag.
A valve manifold is just a group of valves in one valve box. A backflow prevention device is usually required when installing a sprinkler system. Check your local building codes to determine the requirements in your area.
Run all of the station supply pipes and install the sprinkler heads into their planned locations one zone at a time. If a PVC pipe needs to be cut, use a PVC pipe cutter. Exact techniques will vary depending on the brand of sprinkler heads you will be installing. When all of the stations have been installed, run water through each station individually to clear any dirt and debris from the system. Look at each joint to be sure no water leaks out of them. Backfill all of the trenches and replace the grass to patch over the grassy areas.
Turn on one station at a time by manually opening the manifold valve with a pair of channel lock pliers; adjust the sprinkler head coverage as needed.
Install the timer in a garage, shed, or any other convenient location by hanging it from the wall on a nail or a screw. Run 18-gauge multi-strand burial wire from the timer to each valve manifold. Connect the burial wires to the valve wires by twisting them together and by using grease caps to keep the water out of the electrical connections. Strip the insulation off of the ends of the wires with wire strippers and bend a hook into the bare wire with a screwdriver. Hook the wire around the appropriate station screw in the timer box and tighten the screw. Note the coverage location of each station. Repeat this process for each station. Plug the timer into an electrical wall outlet. Set the timer according to manufacturer directions. Test the functionality of the timer by manually turning each station on using the manual feature of the timer.