I have a big garden ( 150 x 150 feet ) so there is a lot of hose lying around. Down the middle of the garden is a grass path where the main hose usually is. Since the grass needs to be mowed, the hose needs to be moved. I have move this hose a lot of time, and occasionally forget. I am very good at fixing hose. ( I have an instructable telling how: Great, Easy and Cheap Hose Repair for the Garden and Elsewhere or just Google "great hose repair" ) Another disadvantage of a long hose is that you loose water pressure, watering takes longer and sprinklers have short range. The underground hose is a way of avoiding both the pressure loss and the need to move the hose out of the way of the mower.
The basic idea is to put well pipe ( this is cheaper than hose and comes in 1 inch inside diameter for great water flow ) about a foot underground. Wherever you want to attach a hose to go off to your plants you have a water outlet ( called hydrant ) underground with a flush cover that you can walk on and mow over. You still have some hose, but it can be much shorter and easy to get out of the way.
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Step 1: Tools and Materials
- 1 inch plastic well pipe
- combination tee – one for each hydrant or water outlet
- hose bib – one for each hydrant
- misc. 1 inch well pipe fittings to suit your needs
- clamps for the well pipe fittings
- 1 ft square concrete tiles – two per hydrant
- ¾ inch exterior plywood for hydrant caps
For The trench
( your exact mix may vary )
- Shovel – suplement with backhoe if you can
- Heavy Duty Hoe
For The pipe
- Propane Torch
- Screw Driver and or tools for clamping
Step 2: Overview
There are several ways to approach the build, you can dig all of the trench, then add the pipe, then the fittings..... or you can complete the project section by section ( which is what I did ). Because approaches can vary I will describe the steps separately in the sections that follow, but this does not imply that this is the order for the build. Figure out the best combination of steps that will work for you. If you build in sections you can use the finished part as you continue to build and have less mess at any one time. It probably also takes a bit longer for the complete build.
Step 3: Making the Trench
Because the hydrants are about a foot down I put the hole pipe at that depth. This is not enough to prevent freezing in my climate, so if you make it less deep, with just a dip at the hydrants you might have just as good results with a lot less work. Consider it. You could even avoid the dip for the hydrants, but I wanted to get the hose bib and the end of the hose all underground, so as to have the minimum of stuff above ground to get caught on the mower.
If you do go a foot down you will find that a 1 foot trench 150 ft long is a lot of work, especially in rocky New England soil. I happen to have a backhoe so it is still possible for me to do the digging. If you do not have one consider renting equipment. There are special diggers for putting in irrigation pipe these may work as well. I will just describe my process, make adjustments to fit your circumstances.
I scrape the turf off into one pile, the dirt and rocks ( a lot of rocks in my case ) in another pile, the piles run down the sides of the trench. Then I carry away the larger rocks that I do not want back in the trench.
The bottom of the trench then needs to be leveled off to a uniform depth. Then pipe can go in.
Step 4: Pipe and Fittings
Unroll the pipe and put it in the trench. It wants to roll up again so weigh it down with some rocks. I worked from the water source to the far end, this makes it easier to test as you go.
Along the length of the pipe you want to install valves and faucets. Where I want a hydrant I install a combination tee. It has 2 1 inch connectors for the pipe and a ¾ thread for the hose bib. It can be hard to get the tee into the pipe. Some soap on the connection helps but my “well man” always uses a propane torch, so I do too. Just soften the pipe, do not burn it.
When the connector is in place use a hose clamp to keep it in place. I used wire clamps as described in Great, Easy and Cheap Hose Repair for the Garden and Elsewhere, but any heavy duty clamp should do.
You can screw in the hose bib now too, pay attention to make sure it has the orientation you want. Mine is set up to come out the hatch I will place over the hydrant. The whole thing is installed about a foot down where the pipe runs. Look at the pictures for more info.
I usually close off the far end of the pipe and pressure test for each hydrant, but this is up to you. The bib I choose has a very large opening for the valve and the ¾ connector offers little resistance to the water flow, you can use smaller bibs, just make sure the combination tee fits the bib.
Step 5: Hydrants Enclosure
This is the hole and hatch to cover the hole ( with a gap to just let the hose in and out ).
You want the hole to stay open, but want to be able to walk and mow over it without problems. I use 1 foot square cement tiles I got at Lowes on each side of the hydrant space. Some 2 x 4 's maintain the spacing at about 10 inches.
I add a plywood hatch to cover the hole, it has an opening for a hose. The hatch is made of 2 sheets of ¾ inch plywood. The lip on the hatch holds it in place on the cement tiles. I think you can figure this out from the picture.
Step 6: Filling the Trench
The filling would be much easier if there were no rocks, I could use the back hoe/ front end loader, but I do not want to put the rocks back, so I use the heavy duty hoe to pull the soil back in and load the rocks into the front end loader. Because of the loss of the rocks I also haul in additional soil to make up for the loss.
The last bit is to put the turf back in place. Pay particular attention to the bit around the hydrant to make sure you have your depth, etc. right. Do not fill in the hydrant space, this would make it difficult to attach the hose. Repeat this until you have all the hydrants you want ( if you are not doing the whole length at one time you can cap the end of the pipe and come back to finish another time ).
A few months later you cannot see any sign of the trench except at the hatches.
Step 7: Use and Some Final Comments
In the winter the pipe may freeze. In my climate the frost depth is much greater than a foot. The standard advice is to shut off the water and blow out the pipe with compressed air. I have another installation, at an even shallower depth that I often do not blow out. But I do detach the hoses, and open all the hydrants. It has survived 10 years, your results may very.
Over time the ground may settle and require adjustment of the soil level. Plan on it, unless your luck is always great.
The hydrants may need some adjustment once the soil has set up a bit, wood used will deteriorate over time but should last years.
I finished this about 2 years ago. In use it has been great. No problems with freezing, leaking, etc. Some of the holes at the hatches have caved in a bit, it has been easy to dig them out again and they have been fine.
I may paint the hatches, either to make them blend in ( green ), or perhaps easier to find ( orange ).
Now I have eliminated 200 feet of hose that had to be dragged around regularly and repaired from time to time. Better water pressure with this system too.
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