What you need to know before adding a water feature to your garden

Small water features probably cause more anguish than most other garden showstoppers. Whether you are putting in an elaborate, high-end affair or a simple bowl for wildlife, it is worth being armed against possible pitfalls. Few gardens come alive without water, and it is hugely satisfying when it really sparkles.

Before you start, you need to decide what level of perfection you want. If you have an uber-smart, modern garden with perfect, clean paving then it is likely you do not want your water bowl to have mosses and green algae accumulating on and around the bowl and water splashing onto adjacent hard surfaces, creating weathering and discolouration.

Conversely, if your garden is more natural and organic in style, you may well enjoy the look of a bit of encrusted moss and algae (which provides ideal drinking sites for bees and insects), and the option of a low-maintenance water feature that just requires you to clean it out manually from time to time. If so, then a low-tech, inexpensive approach will be the obvious route to go down.

The latter is my approach in my own garden. My “natural” pool keeps itself pretty clear due to the marginal and aquatic plants and the size and depth of the water. I may add some Aga AquaBio (agagroup.co.uk) when the water temperature is between 10C and 16C; this is calcium sulphate and it helps the aquasoil (gunge in the bottom) to become aerobic, instead of the putrid-smelling anaerobic matter it can become. It also reduces the volume of this sediment, so I never have to clean it out. I top it up from a convenient nearby tap on a weekly basis in hot weather. Occasionally, in spring, if it becomes very warm, and as there is no shading from trees, it may have outbreaks of blanket weed, which I remove. I net off the leaves in autumn if I have time. The pool looks superb even in winter as it bounces extra light into the garden; ducks, woodpeckers and myriad other birds, insects, frogs and toads enjoy it as much as I do.

I have added a new water bowl to my garden recently (from Russell Wood Antiques), after noticing lots of dead bees in my water butt this summer, which drowned while trying to drink. I have floated some netting on the water to help keep them out, but the water bowl will provide a safer drinking place for them. It is near my new perennial meadow, which I laid last week from turf. It consists solely of flowering plants, with no mowable grasses and is sure to bring in many more bees; in fact, it is already flowering. I have added lots of pebbles in the water bowl so that the insects and the birds have easy shallow access. I may scrub this out occasionally and definitely will top it up; but when it goes green I will probably turn a blind eye.

Here are some things to bear in mind before you add a water feature to your garden.

Fountain rules

When you install a fountain you may well lose water from splashes when gusts of wind carry the water beyond the pool/tank or bowl. There is a basic formula: the height of the fountain should not be any higher above the water surface than the radius of the pool. For instance, if your lion’s head spilling water into a pool is a metre higher than the pool, make sure the radius of the pool is at least one metre. It is not a foolproof formula, though; on windy sites you need more, and fountains that have a fine rose pattern will spread water further than solid, stable columns of water.

Mike Tillett of Tills Water Features has developed several water features with moving water but which do not splash. The Specular is a beautiful piece, which is reflected in the cost (£6,995). There are no cable glands to wear out and the pump is within easy reach for maintenance.

Lighting

Water features can become magical at night when lit, but ideally lighting should be done in such a way that the fitting is not visible during the day. LED pool lights have changed underwater lighting dramatically, as you don’t have to change the lamp. They last for around 50,000 hours on the domestic range – approximately 34 years. The fittings are less noticeable too.

Using the sound of water

If you want to use a water feature to mask less pleasant noises, such as traffic, you need to decide whether you want a small fountain with a dribbling and trickling sound, or a big bore fountain that creates implosion and generates a lot of noise. It is not always easy, however, to get the right level of volume. Tillett recounts the time when he set up a fountain to drown out noise from a busy nearby road. The client initially loved it; then when he popped in a few weeks later, he noticed that the fountain had been turned right down. The noise from it was driving the clients mad, more than the road noise did. He finds this happens often, as when you become tuned into the water noise, you pick up the sound when it is at quite a low level. A sound engineer advised that one of the best ways to drown out road noise is to increase birdsong – putting in some water accessible for birds and insects is one of the best ways to do this.

Keeping it simple

Quite a few firms sell large water bowls with integral pumps and filters, so all you need to do is put a plug on the cable and plug it in. These do not involve digging out underground tanks to hold a water reservoir, whereas the more complicated water bowls and features do. Excellent examples are made by Capital Garden Products (from £512) and A Place in The Garden (from £1,595).

All about pumps

I chatted to Charlotte Earey, from the helpline at Oase (01256 896886; oase.com), a company that supplies pond equipment. This is an extraordinarily useful, free facility, which is always answered by knowledgeable, informative staff.

Charlotte said the foremost question they are asked is why customers are experiencing a low flow from their pump. Pumps contain impellers, which are constantly under friction and will eventually wear down or break over time, especially if they are pumping debris. It’s recommended that you check your pump and clean out any debris a few times each year, or maybe more if your filtration system is not efficient. You may need to replace the impeller if it has worn down, to ensure your pond pump is working at its best.

With most small pumps and filters, in fish- and plant-free pools, do make sure to use Oase’s non-chlorine-based water cleaner AlGo Fountain Clarifier. Many people just throw huge quantities of chlorine-based products into the water, but chlorine at high levels will corrode the pump parts (lower levels of 1.5-2ppm chlorine are acceptable). The Oase AlGo prevents limescale deposits and keeps the water fresh and clear: however, it is not compatible with fish, plants and biological filters. The pump will need to be cleaned and checked every two months, and the bulb on the UV filter should be changed annually. The Oase pumps come with a five-year guarantee and are excellent value, but do need maintenance.

The Filtral submersible filters from Oase can be used with fish and plants too if required: the filters basically contain sponges and a ceramic media to ensure mechanical and biological cleaning. There is also an ultraviolet light to keep the water clear. These filters sit in the base of the water feature and can be discreet. Easy access is needed for the simple but regular maintenance required. For larger, more sophisticated set-ups, the filters and pumps are usually housed separately but nearby, which inevitably involves some careful placement and concealing, which adds to the complexity and expense of the design.

Keeping water topped up, and identifying leaks

If a water feature’s water levels are low, you may think it has been leaking, but in reality the loss can be due to evaporation. To check it, mark the level and measure how much water has disappeared over a set period of time. If it’s a leak, then usually the water drops to the point of the puncture. You can then trace the water line to discover exactly where this is and then reseal it with a patch or similar.

Replace any evaporated water by topping up small amounts regularly (ie, weekly in summer) so you are not adding a lot of chlorinated water in at one time. A lot of chlorine will upset the balance of the water for wildlife.

Some water features have to have the water level maintained at a critical level. If this is the case, or if physical regular topping up is problematic, then installing auto top-ups using solenoid valves is the way to go. These are extremely expensive – at least several thousand pounds – and can be tricky. Tillett says it is down to quality and correct fitting. He recommends Bürkert and points out you will need a separate tank to top up from to ensure that no pool water goes back into the mains – this is a good part of the costs.

Safety

Safety with children is paramount. We installed an invisible underwater grill (using reinforcing mesh) just below the surface of our pool when the children were little; the plants grew through it. Since then there are systems on the market such as Safapond, which I have installed in informal, natural-type pools with soft planted edges; they are easily accommodated in formal pools too.

Rills are another option, too, where the depth of water may only be an inch or so. When we designed the Wind in The Willows garden at Chelsea back in 1994, we had three types of “safe” water: a shallow pebbly rill, a deep pool with a safety grid, and a drainable natural-looking paddling pool. All these techniques I have used subsequently.

Decommissioning

In the UK it was often recommended that you decommission water features in winter. Today, though, if the water feature is moving, it would be highly unlikely to freeze, so it is better to keep it running. With still water features, if ice forms, it will expand as it freezes, possibly causing cracks to the structure. The old remedy of putting a tennis ball or football in it does help: not only does the movement of the ball on the surface help stop complete freezing, but it will also help absorb the expansion of the ice on freezing. In really cold winters you may need to thaw the ice gently to prevent decreased oxygen levels to wildlife under the ice, or maybe use a pool heater. In the East Midlands, over the last 40 years, I have melted the ice a handful of times at most.