Water Filters For Irrigation: Do You Need One & Where To Place It

Along with soil quality and an ideal environment, water is one of the most important components in an irrigation system, be it on a small lawn of a front garden or in extensive farmland that grows vast amounts of crops. Water makes plants and crops healthy, so the water filter installation is critical. Proper installation will allow the filter to work effectively to improve the water quality in your irrigation system.

A water filter is essential in any home irrigation system, and it’s the main component to filter out potential pollutants and debris in your water. In your home irrigation system, the water filter should be installed after the pressure tank and the water pump.

This article explains how you can install water filters in an irrigation system to maximise its effectiveness. It also explains comparable standard systems when it comes to the installation of water filters.

Table of Contents

Do I Need a Filter in My Irrigation System?

A filter is necessary for any irrigation system to prevent toxins and contaminants from leaching into your water supply. Unfiltered toxic substances in poorly installed irrigation systems can be disastrous to the health of your plants, or even yourself.

Plants are living organisms, which means they need clean water to survive and stay healthy. The problem is that through natural or human-caused actions, many water sources have become contaminated or polluted. In addition, the chemicals that pollute water are toxic to plants. As such, it’s essential to keep the water quality high, which means water should be clean; adding an irrigation water filter to your system can help achieve this.

In addition, dissolved or suspended solids can accumulate in pipes, hoses, and valves. In time, the accumulation can cause a blockage. In some cases, the blockage is so severe that you are left with no option but to cut down the affected pipe and replace the clogged pipework or fixture. Unfortunately, removing the clog or replacing the pipe requires a massive amount of time, money, and effort. Both of these options can be tedious, and if used for commercial purposes, can cause delays to your operation.

The best long-term solution that saves you money and keeps your irrigation system in excellent working condition is to install a water filtration system. A filter is a device that separates solid matter and fluid from a mixture by using a specially structured chamber that only allows fluid to flow through it. As a result, solid particles cannot pass through the tiny gaps or holes in the medium, preventing blockages.

It’s important to note that these oversized particles form a solidified mass known as a “filter cake” on the filter over time. The filter cake can block the filter window, reducing or even preventing the fluid from passing through. Therefore, the filter needs to be regularly cleaned to continue working efficiently. Thankfully, cleaning a filter this way is quicker, cheaper and easier than trying to remove a blockage that’s formed further down the pipes of your irrigation system.

Water pump filters should be cleaned every 6 to 12 months. This is the most efficient way to keep your filters and your water cleaner for longer, while improving the life of your filter and your system. However, if you are concerned about forgetting to clean your filter regularly, you can invest in custom built self-cleaning strainers for your filtration system, which will drastically reduce how much manual cleaning you will need to do, and how frequent it needs to be done.

What Types of Irrigation Filters Are There?

When it comes to filtration systems used in an irrigation system, including rainwater tank filters, there are several types to consider. Which filter you choose depends on the initial quality and the features of your water source:

Screen filters – often use a stainless or plastic mesh to strain out solid particles.

Disc filters – often comprise a series of discs stacked on one another and compressed on a rigid spine. Each disk has grooves that run opposite the adjacent disc. As water flows through the disc system, the contaminants are trapped in the grooves. Disc filters such as the Netafim Arkal disc filter can act as stand alone or modular units for greater water filtration.

Sand media – often uses a bed or layer of sand, pebbles, or charcoal to collect contaminants. Periodically, the sand filter is backwashed, forcing water to go back through the bed and dislodging the trapped sediments.

Reverse osmosis (RO) membrane – a porous material that separates ions, oversized particles, microbes, and unwanted molecules from water.

With a range of water filtration equipment for sale in Australia, choosing the right kind of filter for your needs is important.

Care must be taken to choose the right filter – considering inlet/outlet size, flow capabilities, friction loss, maximum working pressure, type of fluid it will filter, particle size allowed through/mesh or micron size of the filter, screen or disc type and so forth.

Just like it is impossible to grab any old filter off the shelf for your car, using any type of irrigation filter just won’t do. An incorrectly specified filter can end up being a very costly exercise, but the correct one can save you in time and money.

What Is The Correct Water Filter Placement?

In your irrigation system, your pressure tank should be installed first, followed by your pump, then finally the water filter.

To ensure that your filter functions effectively and efficiently, it should be installed correctly and in the right place. Here’s a helpful guide on where you should place your filter.

Should I Install My Water Filter Before Or After The Pump?

In general, all filtration systems should be installed after the pump. That’s because filter vessels are usually pressure vessels and not vacuums. These filters require a certain amount of pressure that the pump produces to function optimally.

Installing the filter before the irrigation pump works fine at first; however, it limits or even blocks the water from getting through the pump once it traps enough sediment. As a result, the pump may wear out sooner than its expected life span. In some severe cases, the pump housing may even collapse.

Should I Install A Water Filter Before Or After The Pressure Tank?

If your irrigation system has a pressure tank, you have to install the water filter after it. If it’s positioned before the pressure tank, its location may negatively impact its efficiency because it won’t be able to backwash automatically. The filter requires a different amount of pressure and flow.

If installed before an auto-start pressure tank, the pump may turn on automatically. That’s because the pressure switch is often located on the pressure tank side of the check valve.

If installed after the pressure tank, there’s a tendency for the water to flow backwards from the pressure. The flow would then go into the iron filter control valve through the outlet pipe, damaging the valve. Captive-air pressure tanks fill and empty through the bottom. Because of this, there’s little or no sludge that collects in the pressure tank.

In conclusion, it’s best to install the filter after the pressure tank to achieve the best result, increase the system’s longevity, and ensure proper operation.

Should I Install A Water Filter Before Or After The Softener?

Some irrigation systems have water softeners and can have a water filter installed. If your irrigation system doesn’t have a softener, you must apply the softener before installing the water filter. The water filter prevents softening or soaked resin from escaping from the softener. Any resin that escapes the softener is not toxic or hazardous. However, it could cause faucets and pipes to clog up.

It is vital that if the turbidity of the water is high enough—around five NTUs(Nephelometric Turbidity Unit)—it is necessary to plug the softener. In this case, you need to install a filter. The softener itself acts as a filter, trapping most of the turbidity, but any caking could be backwashed out of the softener with each regeneration.

Should I Install A Booster Pump Before Or After The Water Filter?

If your irrigation system has a reverse osmosis membrane filter, it should be installed before the booster pump; if you have standard filters, the booster pump should be installed between the first and second stage filters.

Doing this will avoid pressure spikes in the booster pump damaging the reverse osmosis membrane filter.

In some cases, you may need professional water pump booster installation to upgrade your irrigation system. As its name implies, a booster pump increases the volume and pressure of water that flows to your irrigation system, bringing your water pressure to your desired level, ensuring a steady supply of water running through your system.

Don’t install the pump before the filter housing. The contamination of raw inlet water may dirty and damage the pump.

Conclusion

Water filtration systems are simple yet effective devices to ensure you are pumping clean, uncontaminated water into your irrigation system. Clean water not only keeps your plants healthy but also makes your irrigation machinery last longer. A top-quality water filter is definitely worth your investment and will save you time, effort and money in the long run.

Do Water Filters Affect Water Pressure?

The right water filter system doesn’t affect water pressure. As long as the filter is clean, you can expect a consistent amount of pressure. Once a filter becomes dirty or clogged, water pressure after the filter cake drops.

However, the water pressure behind the filter builds up. If left unchecked, the backpressure might damage the pump.

That’s why it’s essential to clean the filter system regularly. If the blockage becomes difficult to clean or the sediment has caked to a rocklike state, a new filter is highly recommended.

Do You Need To Filter Rainwater?

If used for irrigation, filtering rainwater for safety, but using an irrigation filter helps avoid pollutants as well as sediment build-up in your system. When collecting rainwater for household use, it’s best to install a household rainwater filter.

Storage systems might eventually get contaminated by debris, mould, algae, and other pollutants. In addition, if rainwater flows from a gutter to the catchment, it may carry sediments and rust. In this situation, a filter is necessary.

It’s worth remembering that rainwater stored for a long time may be contaminated with microbes that can cause water-borne diseases. Because of this, stored rainwater may require UV treatment, although UV treatments do not remove or neutralise harmful chemicals in rainwater.

Disclaimer:

This article is published for general informational purposes only and does not constitute professional advice. Any action you take upon the information you find on this website is strictly at your own risk. Always ensure you have the right qualifications and certifications to carry out DIY work and never put your safety at risk. Hills Irrigation recommends consulting a professional for all electrical and plumbing work.