If you are thinking of installing an in-ground sprinkler system, you must know the exact number of sprinkler heads you’re in need of. You may either use a formula for this purpose or an online calculator for sprinkler layout will get the job done. This will give you an idea of how many square feet does one irrigation zone cover. For irrigation purposes, you must contact utility companies before time to get an idea about the area the irrigation zone is going to cover.

Here are some of the tools you can use for this purpose.

**Layout Planning for Sprinkler System**

“Where to Connect the Sprinkler System?” is the most important and relevant question during the layout planning. For that, you must keep everything in order before time. After that, see what the pressure and flow rate of water is at your place. For better performance, professionals recommend you to keep a pressure of at least 40 Pounds per Square Inches (PSI) for water.

When you are designing the layout plan, sketch your yard first and include all the plants, trees in it. Also, locate the spot where you want the sprinkler heads, pipes and valves to be. Each sprinkler head will cover a specific area, note that down too. Also, note down where the control valve and pipes will be placed. Add pipes’ length also and don’t forget to include crosses and elbows for corners and branches in each circuit. Sprinkler heads will also be in need of threaded risers and fittings.

That’s how you design a layout plan to ensure that sprinkler heads have been placed at the right spot and are provided with the required tools to work better.

Let’s see how you can manually calculate sprinklers.

**Manual Calculation for Sprinklers**

If you want to calculate the layout for your sprinkler system manually, measure the width and length of your yard in feet for determining the area at first. After that, multiply the numbers together. For accurate calculations, it is better to draw/sketch your yard on a piece of paper, a graph paper will be a good option. Take “1 square on paper equals to 1 square foot of lawn”.

Note down each sprinkler head’s distance. If each head distributes water in almost 8 feet circumference, keep a distance of at least 4 feet between them in order to water each part of the lawn. So, the equation is pretty simple, you just need to see the circumference and divide it by 2 to know how much distance you should keep between two heads.

Since you’re using a graph paper, plot out where you want to put sprinkler heads on it. Place them at a distance of 4 ft in each direction. You’ll ultimately end up creating a grid that determines your yard’s layout completely. Counting the number of heads required to cover the entire lawn is the only step left in your manual calculation.

Calculators have arrived just now but for a lay man, it’ll be easy to use manual method rather than indulging himself in complex calculations that may bore no fruit at the end of the day. Also, sprinkler heads aren’t old either, but the irrigation system is what human beings have been using for so long. So, the steps are simple, take a graph paper, a pencil and get to know manually how many square feet does one irrigation zone cover.

**Irrigation Calculator for Landscape **

If you don’t want to calculate the sprinkler heads by yourself, you may use some of the tools available online to do it. One such tool is irrigation calculator for Landscape. It’ll calculate distance you need to keep the sprinkler heads apart. Enter the flow rate of water as well as the pressure in it along with mainline size. But before that, you must know the answers to below-mentioned questions:

- Is the system in need of a backflow preventer?
- Should you use a Sprinkling timer? If yes, how useful will it be?
- How many garden spigots & valves are you in need of?
- Which one does the system use: Rotors or Sprinkler heads?
- Will there be a Stop & Waste System?

After putting the entire info in the calculator, you’ll get the answers to many of the questions. Just don’t let the spray overlap when you are placing sprinkler heads. If you feel any difficulty to use the calculator or to find the answer to any of the above-mentioned questions, just contact a professional. Doing the things yourself is good but sometimes, it can do more harm than good. For calculating the optimum distance, you must know how far the water is going to travel from one sprinkler and how long it will take to touch next sprinkler.

At the end of the day, the lawn is yours and you’ve to keep it safe and sound by any means. So, if you calculate the parameters well enough and then use them accordingly to place sprinkler heads, you’ll be able to water your entire lawn and you’ll end up seeing a lush green lawn full of plants, flowers and trees which is what you actually want.

**How Many Sprinklers Do You Need?**

You must be wondering, how many sprinkler heads you are in need of to cover an entire circle (360°). Note down the dots you marked with ½ circles on the border. Repeat the same procedure now with ¼ circles.

People may also ask “How many sprinklers can they run on one line?”. Both nozzle and sprinkler head won’t consume the same amount of water at different pressures. For example, the usage of water will be 3.11 Gallons/Minute if you use 3.0 nozzle and 5000 series Rotor at 35 PSI pressure. So, if the water capacity at your home is 10 gallons/minute, you can place 3 sprinkler heads/zone.

In order to get an idea of how long you should run your sprinkler system, run it first and note down the time to fill half inch of the can with water. Usually, it takes around half an hour. So, it is better to run your sprinkler system 3 times a week, for 20 minutes per shift in order to provide your lawn with 1 inch of water. For giving it one and a half inch water, repeat the same procedure but with 30 minutes time.

This will help you avoid any wastage of water and your lawn will be full of water which is the need of the hour for it.

**How many Square Feet does a Sprinkler usually Cover?**

The standard sprinklers that we normally use for storage applications cover 100-130 Sq. Feet with one sprinkler head. For extended area or for larger properties (in acres), the range must be increased and may become 144-196 Sq. Feet for each sprinkler head.

The number of sprinklers you can run on one valve depend on the number of zones. For example, if every sprinkler head requires 1.31 GPM flow rate and there are 20 heads in total, you must have 26.2 GPM flow rate or else, the system won’t work well enough. If the system cannot handle more than 16.67, you’ll have to use 2 zones only for covering the same area at your place.

If your yard is large enough in size, at least a quarter acre, installing the sprinkler system will cost you nearly $2500-3000. While for a lawn that is half-acre in size, the installation cost will range between $3500 and $5500. And for one-acre property, the cost jumps to around $8000. So, the variation of cost depends on the kind of sprinkler heads you’re using and the size of your property. Most people require these systems for small lawns in their homes for which the installation is easy and doesn’t require you to pay a large amount.

**Conclusion **

One irrigation zone isn’t measured by the quantity of water, rather we measure the area of zone first and then decide how many sprinkler heads we need to install there and what will be the ideal distance between them. The flow rate of water along with its pressure plays a key role in this regard, the cost also depends on area and is different for larger and smaller properties. So, the best you can do is to draw the sketch of your lawn on a paper, calculate the things manually and start implementing them to have a lush green lawn full of flowers and plants.