Questions to ask a sprinkler system contractor

I sent faxes and e-mails to two local contractors in my area to get bids. View my project Request for Bid.

There are many ways to attach heads to the pipe. The issue here is to use a mechanism that allows freedom of movement so that stepping on the head does not put direct pressure on the pipe (which gets more brittle as it ages). So just screwing the heads into the PVC pipe using a rise is not a good solution. A better solution is to use something like a spring attachment. The best solution is the swing joint. The swing joint allows you to easy move the head around, adjust the angle that it sticks out of the ground, and even change the height after the head is installed. Check out an online tutorial on this topic.

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You should look for 2 types of answers to this question. First, you should find out if the contractor will use spray heads or rotors or a combination. Using spray or rotors doesn't make a difference. But spray heads cover smaller area, so if you have a large area to water and you are going to use all spray heads, it will take many more zones.

The second issue to consider is the quality of the heads. Just like buying cars, there are many qualities of heads available. If you use "Dodge Neon" heads, you can expect to get uneven watering (i.e. wet spots and dry spots) and will need to replace a few heads per season. These cheap heads are the ones sold at Home Depot that cost around $1.25 each. Getting "Toyota Camry" or "Lexus" heads means more consistent water coverage and less clogging. They cost about $4.00 per head and are usually called something like the "Professional Series."

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You need to make sure you like where these will go. You will not need to access them frequently. But you will want to make sure your wife approves of the location. Manifolds will support the full weight of a person standing on them, but they can be a bit ugly and will disrupt your nice sprawling grass patches.

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The purpose of asking this question is not that you are considering adding a drip zone but rather to get an idea of how easy it will be to expand the system. The issues you need to solve to expand the system are:

1. The controller must have a spot for one more zone,
2. The manifold must fit one more valve, and
3. The control wire must have an available wire.

Often contractors will install the minimum system to meet your requirements so this means that if you ever want to expand the system it will be very painful. A well planned system may have an available valve already installed, already wired to the controller. It is always cheaper to put in these extra items when the system is first installed rather than do these improvements later.

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You will want to shut off the entire system at some point. Maybe you are going on vacation or something bad happens (like you carelessly crack a main water line of the sprinkler system with your shovel). The master shutoff must be upstream from the backflow preventer to be effective. Many backflow preventers have master shutoff valves, but they are hard to turn. It is better to have a brass ball valve installed upstream from the backflow preventer.

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The controller of the system is a small computer that you can program with a watering schedule. This box needs to be somewhere accessible (like your garage) and should be placed out of the elements. They do make waterproof controller enclosures, but I recommend that you get the controller mounted on one of your garage walls and get the waterproof controller also (my garage tends to be a dusty place).

The issue with controller wire is a bit different. The controller wire is what runs from the controller itself to the manifolds. These control lines carry the signal to open the valves when the system should water your yard. These wires are about 16 gauge, so they aren't breakable. Usually 7 control wires are wrapped in a waterproof sheath. But you can still mess this up. I recommend routing the wire through your garage through ½" electrical conduit (½" PVC). This will help you not snag it and keep it clean and dry.

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This is an obvious question for all services you get. But with a sprinkler system, you may not want to mess with the small maintenance issues. Many things can and will go wrong with your system. The most common issues you'll encounter, once the system is done, is that the heads will stop functioning. This can be for many reasons. Though this is minor, you'll still need to replace the old head with a new one. You may not want to spend time on stuff like that. Other issues you may encounter are cracked pipes from your shovel or from the cold. Bigger issues may come up, like valves not working or getting cracked. Be sure to find out the response time expected for maintenance calls.

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Anytime you dig a deep trench in your yard you run the risk of damaging tree roots, bushes, or hitting utility lines. Sprinkler systems are particularly bad because the trenches tend to run long distances that transverse your yard. Make sure the contractor explains what they do around trees. Otherwise you might find he/she will use a Ditch Witch and slice all your tree roots.

The issue with grass is another thing. Some contractors peal back the sod for the trenches, others just don't care. If you want your grass to grow over the trenches faster then you need to have the sod saved. But grass will grow back - and grow back faster with your new watering system. So I tend to not think this is a big deal. But you may be less patient waiting for the grass to grow back over. Saving the sod greatly increases the amount of time it takes to dig the trenches and the number of resources required to do so.

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There are three possible answers for this. One is bad, one is acceptable, and the other is great.

The bad answer is if the contractor indicates they will either use 1/2" PVC pipe or something other than schedule 40 pipe for all the piping. In either case, you'll regret it. ½" PVC is too easily damaged and doesn't give good volume distribution. If the contractor doesn't use schedule 40 PVC, he/she might be using schedule 20 - which is too thin and will easily crack. Schedule 80 is overkill for the pipe in the ground.

An acceptable answer is that they will use ¾" schedule 40 PVC everywhere.

A great answer is if the contractor will use 1" schedule 40 PVC for the distribution between manifolds and then ¾" schedule 40 for the individual zones. The 1" PVC allows for better pressure distribution to the zones because it can carry more volume.

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This is a small issue that will help protect your system for a long time. If you bury wire directly in the ground (even though the control wire usually has a protective sheath), it is more likely to get corroded from water, less likely to get eaten by insects or chewed by rodents. The best way to solve this problem is to run the control wire through some sort of protective conduit.

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It would be great if all trenches were 24" deep and each trench carried one pipe. But that isn't the case. Here in Central Texas the ground is very rocky and so you're lucky to get trenches 12" deep. Plus, some trenches carry multiple pipes, so they get stacked up. So a 8" trench with 6 pipes might only be 3" below the ground. The issue is not really about freezing as much as it is about damaging a pipe with a tool - like a shovel or an aerator. The deeper the trenches go, the better.

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