Garden irrigation systems

A garden irrigation system is no longer a luxury reserved for large country estates. UK summers are getting hotter and drier, hosepipe bans are increasingly common across the south-east, and the cost of a single lost border of newly planted shrubs can comfortably outweigh the cost of the system itself. A properly designed irrigation system protects the investment, takes the guesswork out of watering, and quietly does the job whether you are at home or away.

We design, install and maintain irrigation systems across Kingston, Surbiton, Richmond and the wider Surrey area. Most of the systems we install are quietly invisible: pressure-compensating drip line tucked under mulch in the borders, low-profile pop-ups sunk flush into the lawn, a small control box on a sheltered wall, and a smart controller that learns the garden’s needs and turns itself down when it rains. Done well, you stop thinking about watering.

This guide walks through how garden irrigation actually works, the system types we specify most often, what makes a system reliable on heavy London clay, the smart controllers worth fitting, and the rules around hosepipe bans. It is the same conversation we have with clients before quoting a system.

Why install a garden irrigation system?

A few honest reasons clients give us, in order of how often we hear them.

• Protecting newly planted gardens. A new planting scheme costs many thousands of pounds. The first two summers are the most vulnerable, and a missed week of watering in a heatwave can take out an entire border. Irrigation removes that risk.
• Holiday cover. Two weeks away in August used to be straightforward. With the kind of summers we now get, it is the period when a garden is most likely to fail without support.
• Time. Hand-watering a planted garden of any size in summer is an evening job that few people sustain. A drip system delivers the same volume of water in a fraction of the time, and at the right time of day.
• Lawn quality. A lawn that is irrigated through July and August stays green, recovers faster from wear, and looks the way most clients expect their lawn to look.
• Hosepipe ban resilience. Drip irrigation systems are often exempt from temporary use bans (TUBs) when sprinklers and hosepipes are not. We cover this in detail further down.
• Water efficiency. A targeted drip system uses significantly less water than a hosepipe or sprinkler, because it puts the water exactly where it is needed and almost none of it evaporates.

The system types we install

1. Drip line for borders and beds

The workhorse of any well-designed garden system. Pressure-compensating drip line (typically 16 mm, with 2 litre per hour emitters spaced 30 cm apart) is laid through the borders just below the mulch surface. Water is delivered directly to the root zone with almost no evaporation, no leaf wetting, and no overspray onto paths or walls. On any garden with a substantial planted area, this is the first system we specify.

2. Pop-up sprinklers for lawns

For lawns, the standard is a network of pop-up sprinklers buried flush with the turf. They rise when in use and retract afterwards, so the lawn looks and mows as normal. Hunter MP Rotator nozzles are our usual specification: they apply water slowly enough to soak in rather than run off, which matters on heavy clay. A typical small to medium lawn needs three to six heads on one or two zones.

3. Micro-sprinklers for hedges and mixed planting

Small adjustable spray heads on short risers, useful for hedges, large mixed shrub borders and any area where drip line alone would not give even coverage. Less water-efficient than drip, but the right choice for some situations.

4. Container drip for pots and planters

Pots dry out faster than anything else in the garden, often within a day in high summer. A small distribution manifold feeds individual drippers or microtubes into each container. For a garden with significant container planting, this single addition can transform what is realistic to grow.

5. Subsurface drip for lawns

Pressure-compensating drip line laid 100–150 mm below the turf, on a grid. Invisible, virtually frost-proof, water-efficient, and exempt from most hosepipe bans because there is no above-ground spray. It costs more to install than pop-ups, but on a high-specification lawn or a long-term residence it is the better long-term answer.

Smart controllers: the part that earns its keep

The single biggest change in domestic irrigation over the last decade has been the arrival of genuinely smart controllers. A modern Wi-Fi controller (we use Hunter Hydrawise as our standard, with Rain Bird as an alternative) does several things at once. It pulls the local weather forecast and rainfall data and automatically reduces or skips watering when the forecast shows rain. It can be controlled from a phone from anywhere. It alerts you to a leak or pressure drop before damage is done. And it learns the garden’s pattern over the seasons, so the system that ran for forty minutes in July tapers itself in September.

The water savings are real. Independent trials suggest a smart controller paired with weather data and soil moisture sensors can reduce garden water use by 30 to 50 per cent compared to a fixed-timer system, with no visible loss of plant health. Over a hot summer, that is a meaningful amount of water and money.

Water sources: where the supply comes from

• Mains supply. The simplest and most common option. We tee off the existing supply, fit a filter and a backflow preventer (a legal requirement under WRAS regulations to protect the mains supply), and run the system from there. Most domestic gardens have ample pressure and flow for what is needed.
• Rainwater harvesting. A tank, a pump and a feed into the irrigation system. The right answer where the client wants to reduce mains use, where there is large roof catchment, and where there is space for a meaningful tank (1,000 to 5,000 litres for residential). The pump matters as much as the tank: cheap pumps are a frequent point of failure.
• Fertigation. Soluble feed added to the supply through a small injector unit so that plants are fed every time the system runs. We fit this on systems where the client wants a higher level of horticultural input without the labour, particularly on container-heavy gardens and high-specification borders.

The design decisions that decide whether a system works

1. Zoning by plant type, not by area

Designers call this hydrozoning. Lawns need a different watering pattern (more frequent, shallower) than mixed borders (less frequent, deeper). Containers need their own zone. A drought-tolerant gravel garden may need almost no irrigation at all after the first season. Putting everything on one zone means somebody gets the wrong amount of water. A well-designed three to five-zone system handles all of this with no input from the homeowner.

2. Pressure-compensating drippers, always

A non-compensating dripper delivers more water at the start of the line than at the end, and more at the bottom of a slope than the top. On any garden that is not perfectly flat, the result is wet spots and dry spots. Pressure-compensating drippers deliver the rated flow consistently across the whole zone regardless of pressure variation. The cost difference is small. The performance difference is significant.

3. Filtration before the drippers

Mains water carries fine sediment and limescale that will clog drippers over time. A Y-strainer or disc filter at the start of each zone, cleaned twice a year, prevents this. Skipping the filter is a frequent reason for the cheap DIY systems failing within two seasons.

4. Backflow prevention

A non-negotiable. UK Water Regulations (WRAS) require backflow protection on any garden irrigation system connected to the mains. This stops contaminated water siphoning back into the drinking supply if there is a pressure drop. We fit the appropriate backflow preventer (typically a double check valve on most domestic systems) on every installation.

5. Winterisation built in

Pipes that hold water through a hard frost will split. Every system we fit includes a drain-down valve at the lowest point and isolation at the supply, so the system can be emptied each autumn. On more elaborate systems we use compressed air to blow the lines clear. This is one annual visit that pays for itself in the avoided repair bill.

Hosepipe bans and irrigation systems

A Temporary Use Ban (TUB), more commonly called a hosepipe ban, is issued by water companies during drought. Thames Water and Affinity Water cover most of our patch. Under the Water Use (Temporary Bans) Order, the prohibited activities typically include using a hosepipe to water a private garden, fill a paddling pool, or wash a car. What is usually permitted, even under a ban, is watering with a watering can or with a drip or trickle irrigation system fitted with a pressure-reducing valve and a timer.

In practice this means a properly specified drip irrigation system can continue to run during a hosepipe ban, while a hosepipe or unfitted sprinkler cannot. Subsurface drip is the most ban-resilient option of all because there is no above-ground spray to attract attention. Specifics vary by water company and by individual ban wording, so check the conditions of any ban in force, but the principle holds across most of southern England.

Annual maintenance

A well-built system needs little attention but cannot be entirely ignored.

• Spring start-up. Recharge the system, check each zone runs at the right pressure and flow, look for damage from winter or from any digging that has happened in the borders, and reset the controller programme for the season.
• Mid-summer check. Walk each zone with the system running. A blocked dripper, a kinked line or a damaged pop-up shows itself immediately. Clean filters.
• Autumn shutdown. Drain the system, isolate the supply, and on larger systems blow the lines clear with compressed air. This is the single most important annual job.
• Every three to five years. Replace the most exposed components (above-ground micro-tubing, controller batteries, dripper sections that have aged). The mains-buried elements should last twenty years or more.

What to avoid

• Cheap DIY kits without filtration or pressure compensation. They work for a season, then drippers clog or pressure variations create wet and dry spots. The components cost a fraction of a proper system and they perform accordingly.
• Oscillating sprinklers as a fixed solution. Inefficient, prone to overspraying onto paving, and the first thing a hosepipe ban prohibits.
• Watering at midday. Up to half of the water can evaporate before it reaches the soil. Early morning is the best time, late evening the second best. A timer makes this easy.
• Daily light watering. Trains roots to stay near the surface and makes the garden more vulnerable to drought. Deep, less frequent watering is what builds drought resilience.
• Skipping the backflow preventer. Not optional. It is required by law and protects the public water supply.

Frequently asked questions

Can I use my irrigation system during a hosepipe ban?

In most cases, yes, if the system is a drip or trickle irrigation system fitted with a pressure-reducing valve and a timer. Subsurface drip is permitted under almost every hosepipe ban because there is no above-ground spray. Hosepipes and standard sprinklers are prohibited. Always check the specific wording of any ban issued by your water company, since terms vary slightly.

How much water does an irrigation system use?

A properly designed drip system typically uses 30 to 50 per cent less water than a hosepipe or oscillating sprinkler delivering the same effect. A smart, weather-aware controller saves a further significant amount by skipping cycles when rain is forecast. For most domestic gardens the increase to a metered water bill is modest, often less than people expect.

When is the best time of day to run an irrigation system?

Early morning, between 4am and 7am. Evaporation is at its lowest, plants take up water through the day ahead, and leaves dry before evening which reduces fungal disease. Late evening is the second-best option. Midday watering loses up to half the water to evaporation.

Can I add liquid feed to the irrigation system?

Yes, this is called fertigation. A small injector unit fits inline with the supply and meters soluble feed into the irrigation water at a controlled rate. It is particularly useful for container-heavy gardens, hungry crops in raised beds, and high-specification borders. The feed used must be irrigation-grade and fully soluble to avoid clogging the drippers.

How long does an irrigation system last?

The buried elements of a properly installed system, the mains-grade MDPE pipework, the valve manifolds and the backflow assembly, will typically last twenty years or more. Drip line within the borders and any above-ground micro-tubing has a shorter life, typically eight to fifteen years before sections need replacing. Smart controllers tend to be the limiting factor on lifespan because the technology moves forward, but the underlying pipework outlasts several generations of controller.

Does an irrigation system need planning permission?

No, not for any domestic garden installation we have come across. The only regulatory requirement is the WRAS backflow protection on the mains connection, which any competent installer fits as standard. If you are on a private water supply or in a listed building, the position can differ and is worth checking before commissioning work.

Let’s design a system that quietly does the job

If you would like a garden irrigation system designed and installed for the way you actually live and the garden you actually have, we’d be glad to talk it through. Flourish Landscaping designs, installs and maintains irrigation systems across Kingston, Surbiton, Richmond and the wider Surrey area. See our garden irrigation service page for an overview of the service, or read our companion guide to drought-tolerant gardens for the planting side of the same question.

Contact us to arrange a consultation and start the conversation.