Can I connect a water hose to an irrigation system?

Question

I am planing to install water lines as you can see in the picture. Right now I I have a water hose that runs along the house, I am referring to the segment that goes along the wall between the patio and the house.

The other two segments together with this one are what I am planing to install.

For now I just have a water hose that I run along the line above described. There is a gap space between the house and the patio where a pipe/water hose fits just fine. My plan would be to install the first segment of the future irrigation system and to connect the water hose to it for now (no sprinklers so no water pressure loss) because I want to cover that gap with peanut size decorative stone. Later I would disconnect the water hose and fully install the irrigation system. As an alternate solution I would love to leave the water hose there till I proceed with the irrigation system plans but I am afraid that the water hose is not winter resistant, so my question is: can I put an irrigation system segment there and connect the water hose to it at at the point where the irrigation line reaches the corner of the house?

Answer 1

I'm actually wanting to do this myself. I've looked into it for quite awhile. There is one video on youtube that is amazing. His system has been up for nearly 5 years without any problems. I'm at work and cant search youtube, but if you look up "150$ diy irrigation system" you will find it.

Some things to consider.
1. Water pressure from the garden hose won't be able to support more than 1 (maybe 2) sprinklers at a time. Depending on the type and GPM you get at your house. Test this with a 5 gallon bucket, I'm able to run one rotor 50ft throw and 2 very tiny low pressure nozzles at the same time.

2. If The larger pipe or hose you use, the more pressure you get. I just bought 1 inch irrigation hose with an adapter to 3/4 inch for the sprinkler. I have a smaller yard, so I can get about 90% of the yard with one 50ft throw sprinkler. The smaller the diameter of the main, and hose the lower GPM you will have.

Edit Okay for people who think smaller water pipes will increase water pressure, no. It's about fiction, volume and speed. Below is a great read about it, with some quotes.

https://www.irrigationtutorials.com/using-a-smaller-pipe-to-increase-water-pressure/

Grab your thinking caps for this. As you well know, Bernoulli’s Principle essentially says (paraphrased) that as the speed of a fluid increases, the pressure of that fluid decreases.

Obviously as you force a given amount of water through a smaller size pipe, the velocity of the water must increase for it to get through the smaller pipe. According to Bernoulli’s Principle that will decrease the water pressure! This is called the Venturi effect. By suddenly forcing the water through a narrow passage you can actually create enough of a pressure decrease that it creates suction. This is how many fertilizer injectors work. It also is another reason why using a smaller pipe would not increase the pressure– it would actually decrease it!

Answer 2

Ok. The pressure is coming from the supply system. First consider situation #1. #1. Why can't the garden hose handle more than 1 or 2 sprinklers?

A. Well basically increasing the number of sprinklers increases the flow needed. And your system can't handle that increased flow.

B. This seems a bit complex or confusing, as adding more sprinklers because the system can't handle the flow, you will actually see a pressure drop in your system.

#2. Larger pipes will support larger flow. But really the reason is friction.

A. Start by filling water into your 3/4" and 1" lines. With no use, but allow an air bleed. The 1" line will take longer for your source to fill, up. But once both lines fill up. Both will equalize with the source pressure because there is no flow out of the pipe.

B. Now add a sprinkler to the system. Fluid is now flowing through the pipe from supply to user. The user needs a particular gallons per minute or cubic inches per minute. To get the average flow velocity, cubic inches = inches per minute x pipe area. Larger the pipe area the lower the flow velocity. Velocity results in friction with the sides of the pipe, more velocity more friction. And this friction causes a pressure drop. So the larger pipe see a much lower pressure drop (Area = 1/4 x Pi(3.14) x Dia^2) . When the pressure drops to zero the water at that point has push from behind and doesn't move. This occurs at a sprinkler or user, and not getting enough pressure results in less than rated flow. Note: the supply is greater than the users.

C. Keep adding sprinklers and eventually the source can't keep up basically the initial supply in the system is used up, and then whatever the supply can push into the system is used as fast as it's entering. Typically this results in reduced pressure, and sprinklers close to the source having noticeably more power/pressure than those further along the system.