Does a Garden Irrigation System Need a Pump and Tank?
When we first discuss a new garden irrigation system with a customer, one of the most important things we need to understand is the available water supply.
It is easy to assume that an automatic watering system can simply be connected to an outside tap. For some smaller systems, that may be perfectly suitable. For larger gardens, however, the available pressure and flow may not be enough to operate the system effectively, particularly where several sprinklers or watering zones are required.
That is why every successful garden irrigation installation starts with understanding what needs to be watered and what water supply is available to do it.
Why Water Pressure and Flow Matter to Irrigation Design
Pressure and flow are closely related, but they are not the same thing.
Pressure is the force pushing the water through the system, while flow is the volume of water available over a given period. You can therefore have an outside tap that appears to produce good pressure but does not provide enough flow to run several sprinklers effectively at the same time.
Mains water pressure can also vary. Ofwat notes that pressure can be affected by factors including the elevation of a property and how much water other customers in the area are using. During periods of particularly high demand, the pressure available at a property can change.
When we design a system, we therefore look at the available supply alongside the number and type of irrigation zones required. We do not simply select sprinklers first and work out the water supply afterwards.
Can a Garden Irrigation System Run Directly From the Mains?
Yes, some smaller garden watering systems can operate directly from the mains if the available pressure and flow are suitable.
TCR installs systems ranging from straightforward watering arrangements through to fully automated installations, so there is no requirement for every customer to have a tank and pump. Our own guidance on irrigation water supplies explains the different sources that can potentially be used, including mains water and stored rainwater.
A smaller system might operate one watering zone at a time and work perfectly well within the available supply. As the garden, number of sprinklers or watering demand increases, however, the limitations of a direct mains connection become more important. TCR specifically notes that small irrigation stations may be able to run directly from the mains, subject to the available supply and relevant requirements.
The important point is that garden size alone does not provide the answer. The supply needs to be assessed before the system is designed.
When Does an Irrigation System Need a Pump and Tank?
Larger irrigation systems will commonly use a storage tank and pump.
The tank creates a stored supply of water for the system, while the pump provides the pressure and flow needed to operate the irrigation equipment. This can allow larger sprinklers or a greater number of sprinklers to operate effectively than would be possible directly from a limited mains supply.
At TCR, we design pumped irrigation systems for installations where this type of setup is required. Depending on the system, pumps can be installed within the tank or housed separately, and either fixed-speed or variable-speed equipment may be appropriate.
This is particularly relevant for larger gardens, estates or installations with several lawn and planting zones. Rather than reducing the system design to whatever the outside tap can support, a properly specified pumped system gives us greater control over how the irrigation network operates.
How Do We Choose the Right Tank and Pump?
There is no standard tank or pump size that will suit every garden.
We need to consider how much water the system will use during its planned irrigation cycle, how much water is entering the tank while the system is operating, the flow required by individual zones and how quickly the tank can recover between watering periods.
It is also important to distinguish between a tank’s overall storage capacity and the amount of water that is actually usable by the irrigation system. TCR’s guidance on tank and pump sets explains why this needs to be considered as part of the wider system design rather than choosing components in isolation.
Space matters too. The position of the tank, pump and associated equipment needs to work with the property and the garden, so these details are considered during the design stage.
Can Rainwater Be Used for Garden Irrigation?
Yes. Where the property and proposed installation allow it, stored rainwater can be incorporated into a garden irrigation system.
Rainwater collected from roofs can be stored and then pumped into the irrigation network. TCR designs systems that can make use of harvested rainwater, and our water supply options include rainwater alongside mains and other potential sources.
The available storage and likely irrigation demand still need to be assessed properly. Rainwater is not an unlimited resource, particularly during prolonged periods of dry weather when the irrigation system is likely to be needed most.
For that reason, rainwater harvesting needs to be considered as part of the overall system design rather than simply connecting a small water butt to a large automatic installation.
What Do UK Water Regulations Mean for Irrigation Installation?
The way a permanent irrigation system connects to the mains water supply also needs to be considered carefully.
Backflow protection is important because the drinking-water supply must be protected against contamination from water within an irrigation system. The RHS notes that outside taps need appropriate backflow protection and that permanent automated irrigation connected to the mains will often require a break tank providing an air gap. Water Regs UK also advises that irrigation installations need to be considered according to their design, size and level of backflow risk.
The appropriate arrangement depends on the individual installation and requirements of the relevant water undertaker. This is another reason why a permanent irrigation system should be properly designed rather than treated as a simple extension of an outside tap.
What Do We Check Before Designing Your System?
Before recommending a system, we need to understand the garden as a whole.
That includes what needs watering, the layout of lawns and planting, the available water source, pressure and flow, the number of watering zones required and where equipment such as tanks, pumps and controllers could be positioned.
We also consider the different watering requirements across the garden. A large lawn, a newly planted border and an established hedge do not necessarily need the same method or watering schedule. Dividing the installation into appropriate zones allows the system to apply water where it is genuinely required.
Automation can then be used to control those zones, with TCR able to install systems that take factors such as rainfall, temperature and sunlight into account.
If you are at the early stages of considering irrigation and want to understand the wider process first, our guide to garden watering system installation explains how we approach planning and fitting a system.
The Right System Starts With the Right Water Supply
So, does your garden irrigation system need a pump and tank? Sometimes it does, and sometimes it does not.
A smaller installation may work effectively from the available mains supply, while a larger multi-zone system may need dedicated water storage and pumping to provide the required performance. The right answer depends on the garden, the water supply and what the finished system needs to achieve.
At TCR Watering, we assess these factors before designing the installation so that the system is built around the property rather than relying on guesswork. If you are considering a new garden watering system, speak to our team and we can assess the available supply and recommend the most appropriate setup for your garden.
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