Thank you for being clear and explaining this subject. I have an automatic sprinkler system with 4 zones and my water source is ditch water and is supplied from my HOA. My annual HOA fees pay for the use of this ditch water. The HOA supplies ditch water to each property that is pressurized and each property has a brass shut-off valve to turn water off to the property. This brass shut-off valve is located in the front yard and in the corner of the property where the phone pedestal, cable pedestal, etc. are located. This brass shut-off valve is the point of where the responsibility of the HOA ends and the responsibility of the home owner begins. From this brass shut-off valve my water is carried into my property in a 1 1/4 inch PVC line and before my manifold I have a hose faucet followed by a brass gate valve and then the inline "Y" filter. On the discharge side of the filter this 1 1/4 inch PVC line is reduced to 1 inch and this goes into my manifold. All four valves are 1 inch and the water line coming out of each valve is 1 inch. Since there are numerous properties "sharing" this water at any given time the flow rate and pressure can fluctuate throughout the day. I have my timer set to start watering at 8 pm as this is the time when no one else near me is using water. My flow rate is 6 GPM and the pressure is 20 PSI. As a result, my sprinklers underperform and are anemic in their water distribution on the lawn. Each zone has between 6 and 8 sprinklers. I have determined that the piping in each zone is working properly and that there are no brakes in the piping. The 1 1/4 inch line may or may-not have a brake in the line. I have yet to determine what the status of this line is. My house is on a cul-de-sac and all my neighbors have thick lush green lawns. My lawn is not in the same league as my neighbors. Therefore, my problem seems to be with my system and not with the HOA water. The brass shut-off valve at the front of the property does open and close as I have tested this. This valve is open as far as it can open. Do you have any ideas on how to solve this issue?
Woah thanks now I now how to use the pressure loss table!! Very helpful info me working on an orchard and transitioning into an irrigation store. I can help out my customers even more!!
Hi, thanks for this its pretty usefull! I would like to evaluate the flow from my main line and its not easy to do without cutting it and test... Maybe you already makes the test and have an idea? Its a pex 3/4 (0.681 ID) and around 40 ft long. My static pressure is around 64 psi. For what I think according to tables is that I could have around 14 GPM with remaining 49 psi (12 ft/s and pressure drop of 35 psi/100ft) but not really sure on that! Do you have any ideas? Thanks again!
How do I test the water pressure going to my irrigation and water follow? Testing at the spigot wouldn’t be accurate as the spigot is connected to my house and likely after a regulator, and my irrigation line branches directly off the main water supply line before it comes to the house.
I have a 5/8`water meter and it's 50 feet to the house but I also have 100 feet of irrigation and the sprinkers barely work. Can you upside to 1" from a 5/8" meter or would that not work? Thanks for the great information 👍
hi interesting video of demonstration. please explain more on if the supply pressure is constantly same, why is the flow rate is different from the use of different size of pipe where the smallest pipe has the least flow ? many thanks
Very informative video... I recently finished my irrigation system and I couldn't remember my school/father teaching and I went with someone at the shop's recommendation. Of course, now that I have finished everything I have found that my water pressure is not good enough and my sprinklers won't reach their length. My question is - can I now go from a 3/4inch to a 1 inch pipe? Will the water pressure and flow increase? I connected a 3/4 inch pipe from my front garden to the back, 30 meters long then I installed another tap. From that tap I put a connection with a timer for my irrigation system with another 3/4 pipe. This is the pipe I wonder if I can change to a 1 inch? I hope this makes sense. I really hope you can read my question. Thank you once again for the video Dr Phill.
If my understanding of the video is correct. Then it should increase your pressure if you go to 1 inch pipe. So in that case maybe it's better to install 1.5 inch pipe with a flow regulator to decrease pressure to what you intend to use it at. That way you have max pressure with adjustability. In any case. I'm curious what you did?
I’m also curious what you ended up doing. You may regain a small amount of pressure by switching to larger pipe in the back, but the pressure lost in the 30m of 3/4” pipe is unrecoverable without also up-sizing that pipe.
You certainly can go up in size, but you won’t regain any pressure lost. You’ll simply reduce the amount of pressure that’s lost per foot for the sections of pipe you size up.
