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Irrigation FAQs

ARE THERE WATER REGULATIONS THAT I NEED TO CONSIDER?

The most recent water regulations categorise the different types of irrigation system dependent on the risk of contamination of the mains water supply, within a domestic garden it is okay to operate mini sprinklers and dripline / porous / leaky pipe direct from a tap with the appropriate backflow device. With other types of underground irrigation such as pop up sprinklers a RPZ (Reduce Pressure Zone) valve or more commonly a storage tank and booster pump is required. Please go to the resources section for more information and guidelines.

I WANT TO IRRIGATE USING WATER FROM A WELL / LAKE / STREAM. WHAT DO I NEED FOR THIS?

You will need a pump to move the water and to provide water pressure for your system. You will also need a dirty water filter to make sure that debris (even from the cleanest lake or stream water) does not block your sprinklers. Additional components such as float switches and an electrical control switch will be required and LWS can advise and supply these as a complete kit. Assuming it is a private, domestic property you can draw up to 20,000 litres per day without an extraction license, although you should always check with the local office of the Environment Agency.

DO I NEED TO AUTOMATE MY SYSTEM?

Whatever type of irrigation system you have you will only truly benefit from it if you automate. This is as simple as a tap mounted battery powered unit for small systems or battery / mains powered multizone controllers on medium to large systems. Not only does it relieve you from the chore of watering when you are at home or away, it also ensures your garden gets the right amount of water at the right time. This ensures that you minimise water waste and that the results in the garden are stunning.

WHAT SHOULD I DO WHEN IT RAINS?

Most timers have a button for shutting down for rain. In addition, connecting to a Rain Bird rain sensor allows automatic shutdown during rainy weather.

WHAT MAINTENANCE DO I NEED TO DO ON MY IRRIGATION SYSTEM?

Monthly: Adjust timer settings, check and adjust sprinkler sprays, check surface pipes for leaks and clean mainline filter (if installed).

Once per season: Clean filters in all sprinkler heads, manually operate each valve and check signal cable for any damage.
As needed you should: Unclog sprinkler heads and adjust installation levels of heads to ground level. The system will require draining before winter to prevent frost damage, and a spring service to get it up and running for the new season.

CAN YOU TELL ME MORE ABOUT TRENCHING FOR IRRIGATION PIPES?

A trencher is a machine used to dig a trench in your lawn for irrigation pipes that is usually 6" wide and up to 18" deep. Of course, you only have to go about 8 to 12" deep to bury irrigation pipes (try to achieve at least 6" of cover after pipes are installed).

If possible always remove any existing turf with a turf cutter before trenching, or it is likely to take much longer for your lawn to recover. These are available from some hire shops, alternatively find yourself a good trenching spade and get to it!

HOW DEEP SHOULD I INSTALL MY SYSTEM?

Sprinkler pipe should be installed 8 to 12" below the final surface grade to protect pipes from the elements and possible damage (aeration etc). Pipes buried this deep will still need to be winterized to protect them from freezing conditions.

HOW MANY SPRINKLERS CAN I RUN AT ONE TIME AND WHAT ARE ZONES?

This will depend on your available water supply, the more you run at one time the more water flow and pressure you need. In the USA most systems are run from the city main water supply, in the UK it is more common to have a water storage tank for irrigation with a booster pump. This is generally because the flow / pressure over here is not as good. Small domestic drip and mini sprinklers systems can be run direct from the mains water supply, but pop up sprinklers are normally run via a tank and pump.

In all cases you work out how many sprinklers you need, then work out what their total flow requirement is (all product data is in the webshop), this required flow is then divided by your available flow (either from mains or pump). The final answer will indicate approximately how many zones or groups of sprinklers you will need to run. Remember, the bigger your zones the bigger pump and pipe you will need, but no need to worry, LWS can advise on all these areas!

WHAT ARE LPM AND BAR AND HOW DO I FIGURE THEM OUT?

LPM stands for Litres Per Minute. This refers to the amount of water your irrigation system receives through the pipes. BAR refers to the pressure of water being supplied to your system. Both need to be figured out before you can design an effective irrigation system or submit for our design service. It is always best to take the water and pressure reading yourself in order to provide accurate design specifics.

HOW DO I CALCULATE THE LPM?

Simply you need a bucket of any size (as long as you know exactly what size it is), and a watch with a second hand.

  • Go to the tap that you are planning to use.

  • Make sure there is no water running anywhere inside or outside while you do this test.

  • Turn the tap on fully and place the bucket under the tap.

  • Time exactly how long it takes to fill the bucket.

  • Then, take the size of the bucket in litres and divide it by the time in seconds it took to fill it up.

  • Multiply by 60 and round your answer to the nearest whole number.

  • This is the LPM rate coming into your system.

HOW OFTEN SHOULD I WATER MY GARDEN AND FOR HOW LONG?

Because each garden is unique, the answer to this question can vary greatly. The best watering times and length of watering depends on your climate, the type of grass / planting and soil conditions. It is generally preferable to water infrequently for a longer period of time than frequently for short periods. Watering infrequently provides deep water sources that roots search for. Frequent watering promotes surface root growth. In the UK the requirement can vary from 10mm – 24mm per week (10 – 24 litres per metres squared).

Ask LWS for more information as run time will depend mainly on weather, product type and product spacing. As a rough guide, assuming your spacing of sprinklers is correct, you will find that a 20 minute run time three times a week should be sufficient in average weather. Dripline will only require approximately two hours a week at 50cm spacing. If your system design and product selection is good you will be surprised at how much you can reduce run times and still achieve excellent results.

WHAT TIME OF DAY SHOULD I WATER?

Rain Bird recommends watering early in the morning, followed by evening watering. Water in the middle of the day only if it is cool or if you have a new lawn requiring constant moisture. You only should water more than once per day if evaporation is extreme or if your soil won't hold water because of the clay content or the slope of a hill causes too much runoff.