A loud crack followed by water spraying six feet into the air. A single rock shifted underground and shattered the pipe.
That mistake taught me more about PVC pipe than any book ever could.
What PVC pipe size do you need for each part of your system?
Use 1-inch PVC for main lines up to 15 GPM flow. Use 3/4-inch for lateral lines feeding individual zones. Use 1/2-inch for short branch runs under 50 feet.
60 per foot. 45 per foot.
30 per foot. Match pipe size to your flow needs, not your budget.
Pressure loss increases with smaller pipe. At 10 GPM, a 100-foot run of 3/4-inch pipe loses roughly 8 PSI. The same run in 1-inch pipe loses only 3 PSI.
Use a friction loss chart before every new installation. You can find these online for free. A wrong pipe size means poor sprinkler performance.
Your heads might not pop up fully. Your coverage will have dry spots. support/irrigation-system-design-guide/) for exact calculations.
What fittings connect PVC pipe to sprinkler heads?
You need threaded risers, swing joints, and reducing tees. A threaded riser extends from the pipe to the sprinkler head. A swing joint provides flexibility to absorb ground movement.
A reducing tee drops from the lateral pipe down to the head. 50 each. Swing joints run $4 to $7.
Reducing tees cost about $2. Use swing joints on every head now. They prevent broken pipes when kids run across the lawn. A $7 swing joint saves a $200 repair bill later.
The connection between PVC and sprinkler heads is critical. You need PVC primer and cement rated for pressure applications. Apply primer first.
Then apply cement to both surfaces. Twist the pieces together with a quarter turn. Hold for 15 seconds.
Wait 30 minutes before testing pressure. The typical pressure at the head should be 30 to 50 PSI. Flow rates range from 2 GPM to 5 GPM per rotor head.
What is the difference between schedule 40 and class 200 PVC?
Schedule 40 is thicker and stronger. Class 200 is thinner and cheaper. Schedule 40 handles 220 PSI at 73 degrees Fahrenheit.
Class 200 handles 200 PSI at the same temperature. But class 200 has thinner walls. It cracks more easily under impact.
Use schedule 40 for main lines and valve manifolds. Use class 200 for lateral runs where pressure is lower. Schedule 40 costs about 30% more.
25 per foot. That area takes the most stress.
Schedule 40 also has thicker walls at the fittings. The fittings for schedule 40 cost more too. 80.
50. The thicker walls mean better threads. Schedule 40 threads do not strip as easily.
The adapter cracked and the head spun free. That cost me another trip to the hardware store.
Stick with schedule 40 for anything that threads. Use class 200 only for straight glued runs. support/irrigation-controllers-complete-guide/) for a reliable system.
How do you choose between poly and PVC pipe?
Poly pipe is flexible and freeze-resistant. PVC pipe is rigid and glue-together. 35 per foot for 1-inch.
60 per foot for the same size. Poly uses barbed fittings with clamps. PVC uses solvent cement and primer.
Poly bends around obstacles without extra fittings. PVC needs an elbow for every turn.
Your climate matters too. Poly expands slightly when water freezes. This reduces cracking risk.
PVC becomes brittle below freezing. Use poly for any line less than 12 inches deep.
Use PVC only in deeper trenches below the frost line. Poly connections can leak if clamps are not tight. PVC connections never leak if properly glued.
Both materials work with standard sprinkler components. Both handle 40 to 80 PSI operating pressure. Your choice depends on your soil and winter conditions.
Poly is easier to repair. Cut out the damaged section.
Insert a new piece with couplers and clamps. Takes 10 minutes. PVC repairs require glue drying time.
You wait 30 minutes before testing. That is 30 minutes of standing water in a trench. The poly fix took one trip to the store.
The PVC fix would have taken two. Keep spare parts and fittings on hand for emergencies.