Sprinkler Installation: Getting a DIY Estimate In 3 Steps
You normally start work at 7:00 am and because we’re in Houston you have a 30 plus minute commute… so your morning routine may go something like this: wake up, shower, breakfast (maybe?), coffee (on the go) and out the door. If you are quick about your morning activities and shower at night, you may be waking up at around 6:00 am +/- 15 min. Now think about adding another 10 – 15 minutes to water the lawn in the morning… let’s face it, the lawn will not get watered and you will start each day with a slight feeling of unaccomplishment. Now imagine how much more time you ‘d have in the morning if you had an automatic sprinkler system installed.
An automatic sprinkler system can help you get rid of this feeling… that’s obvious; but where do you start? Who do you call? Do you go with your friend’s reference? Will they speak English? Are they giving you a good price? How many quotes should you get? This article will go over some of the technical details of a sprinkler system installation so you can “ballpark” a price yourself and make an educated decision. So, how do you know if you are getting a good deal and more importantly how can you quickly estimate and filter out different companies? The first thing to do is to understand how many zones your lawn needs. Normally Sprinkler companies charge per zone, but one may tell you, you need 5 zones at 300 $/zone and a different one may say you need 10 zones at 250.
Below are THREE simple steps to help you determine the number of zones you need
1) Determine Flow Rate of your Home’s Water Supply
This is actually easier to do than it sounds, so fear not and keep reading.Flow rate is calculated in gallons per minute (GPMs) and, all you need is a bucket or a container with a defined volume. It’s easy to use something that you may already be familiar with, for example an empty gallon of milk. Now turn off anything using water inside and outside the home (just make sure no-ones taking a shower or using the washing machine, or dishwasher) and turn on the outside faucet full throttle and have a timer ready to measure the time it takes to fill the container or get it to the 1 gallon mark. Finally if you filled the 1 gallon container in 10 seconds that means your flowrate is 1/10 = 0.1 gal/sec. Now multiply this times 60 to convert it to minutes and you have a flow rate of 6 GPMs. Congratulations! You now know the water flow rate to your house. Keep this number handy.
2) Determine Water Pressure of your Home’s Water Supply
If you want to get all technical, you can buy a pressure gauge, hook it up to your faucet and measure your exact water pressure, but because we’re just looking for an estimate, we are going to go with a typical home water pressure of 35 psi. Your water company may also provide this information.
3) Make a Map
This is where you get to use your measuring tape and determine what type of sprinkler heads you need. Our recommendation is to start with a drawing.
Make a map of your front yard and back yard, estimate how many sprinkler heads you would need. It doesn’t have to be exact. Keep in mind that the sprinkler heads should match the watering needs of the plant. For example, if you are calculating sprinkler heads for a lawn, that would be a spray head but if you are setting some of them up for plants or bushes you want to include a mist-enabled sprinkler head as to not damage the plants.
So, calculate how many different zones you need based on the watering needs of the plant. Generally, these are around 2-3, one for the lawn and one for the plants. Then, estimate how many sprinkler heads you would need, and this is where the fun begins.
Once you have an estimate of the number of heads you will need then add up the flow rate that each head will need. Generally, a head will need a flow rate of about 1.31 GPM, so if for example, you estimate you will need 34 heads, your GPM needs will be 22.7 GPM so because your water flow rate can only handle 17 GPM you will need two zones for this particular area. Repeat the same process for all other areas of your yard.
The last three steps should give you a general idea of how many zones your home would need. With this information, you can call the top 5 sprinkler companies in your area and ask how much they charge per zone. The companies should be able to give you an estimated number but keep in mind that this may change based on many variables that affect your home such as terrain, future construction plans such a pool in the backyard, etc. This should only help you plan out a budget for the installation but it should not be the final answer. The numbers should be used for a baseline comparison on who to work with.
Source: Moore, Sarah. “How Many Rotor Sprinkler Heads Can Be on One Zone?” Home Guides | SF Gate, http://homeguides.sfgate.com/many-rotor-sprinkler-heads-can-one-zone-101019.html. 28 December 2018.
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