Top considerations when buying an outdoor pool



As potentially one of the largest components of your garden, the swimming pool requires a lot of thought and planning in determining where to put it. You will need to consider the path of the sun, proximity to trees, ground levels and topography as well as safety and security and the ability to survey the pool from your house. Typically the pool area will include a paved area, landscaping and planting.
A good pool company should be happy to visit and survey the site as well as provide guidance for where the pool should sit and the naturally desired routes any bathers would be likely to take when accessing the pool from the house. The pool location should avoid areas of lawn by the access route so as to protect the pool water from dirt, mud, animal faeces, grass and other debris as this is all potentially carried on bathers feet into the pool and will provide an unnecessary burden on the pool dosing system, not to mention require more regular pool cleaning. Another consideration is where to situate the small plant room required to house the pool equipment which is needed to be kept dry and clean from general garden waste.


The most common outdoor pool size in the UK is 8m x 4m but for those of you who are serious about swimming or have a larger garden a 10m x 4 or even a 12m x 5m may be better suited. It’s worth remembering that the installation costs are directly proportional to the size and a larger pool will also cost more to run. Adding a resistance swim device is a cost effective option for serious swimmers who don’t have space for a larger pool. Irregular shape pools were popular back in the 1980s, however modern tastes tend to favour rectangular pools and these do have some benefits.

The most common type of pool cover on an irregular shaped pool is a bubble cover on a manual roller, these covers can be cut to any shape, are cost effective and good at retaining the heat however, they don’t offer much in the way of safety. If your pool isn’t going to be fenced off, or you’re concerned about safety of children and animals then a rectangular shape pools the best option as it benefits from a wide range of automatic safety covers. Constant depth pools are more cost effective to construct, cheaper to run and allow younger children to use the entirety of the pool. If you’re planning to use your pool for diving then your pool contractor must design the pool chamber to meet the SPATA cage of safety regulations. This will lead to a deeper pool and affect the construction and running cost.



The choices you make during construction will determine the longevity and running costs of your pool. It’s common practice to have an insulated chamber on outdoor pools as this helps to reduce your running costs as well as being more eco-friendly. You’ll need to think about your garden access and logistics of getting materials to and from the site as this can sometimes affect the cost.

The type of construction can sometimes limit the finish on the inside of the pool chamber but this is something that our team of experts can talk you through and find a solution for. Another point to consider is that time of year can play a part in the construction cycle - believe it or not the winter is sometimes the best time for the heavy works as they go relatively unnoticed so you can enjoy your garden in the summer.

Swim Season

The swim season for outdoor pools is typically May to September, but some may prefer an extended season such as, April to October or for the brave - all year round! If your pool is heated by a gas or oil boiler then it’s critical to ensure that the heat demand can be met. If you are heating your outdoor pool by using an air source heat pump then this too needs to be designed to cope with the demand as it is likely to need either a bigger heat pump or multiple heat pumps which will increase the capital cost.

Before asking us to quote for an all year round heating system, have a think about if you’re really likely to be swimming on a chilly December morning as the costs do increase. Our experts can talk you through the options and design a solution to fit your needs whatever you decide.



The typical design standard for water temperature in an outdoor pool is 28°c. In our experience people who swim for exercise frequently and for extended durations prefer the water temperature to be lower, between 25°c to 27°c as it’s more comfortable as your body warms while exercising. However, people who use the pool more recreationally prefer the water to be 29°c to 30°c. The reason temperature is important is because a pool designer will need to calculate the correct sizing of the heating equipment to ensure you can enjoy your pool at the most comfortable temperature.

Technical and Practical Considerations


Planning permission is not usually required to install an outdoor swimming pool as a pool is often considered as a garden landscaping project. However, a good pool contractor will be happy to check with your local planning authority, particularly if your property or the surrounding area falls under any of the following classifications:

  • Designated land
  • National park
  • Greenbelt land
  • Listed building
  • Conservation area

Time of the year

We have a lot of clients come to us and ask for their outdoor pool to be ready by Spring, the start of the swimming season. For this to be possible, the project needs to start in January or before, in fact the best time for the initial works to begin is over the winter period so your garden can be enjoyed in the warmer months. It’s also worth bearing in mind that most pool companies will be booking in projects several months in advance so don’t wait until the sun starts shining, get in there as soon as possible.

At Origin, we also offer a split project programme to help any of our clients who are undergoing a house or garden refurbishment, we split the work into two phases, which allows all of the heavy work to be done at the same time so disturbance is minimised.

Construction Duration

Each duration will depend entirely on the project considerations. If planning permission is required, the general rule is to allow 8 - 10 weeks for the local authority to process and approve the application. However in terms of construction, concrete pools usually take between 10 - 12 weeks. Each project requires a ‘pre-build’ time frame of around 2 - 3 weeks, this is to allow structural engineering calculations, drawings, planning the work and site logistics.

Weather can have a big effect on the build duration as certain tasks are temperature dependent or require dry weather all together. Additions such as levelling a site, retaining walls and paving will increase durations. Ensuring you have good access for soil removal or material deliveries can help reduce the time frame so it’s best to have a solution for this at the beginning of the project.


Access considerations

Good access does assist project speed and efficiency, typical access needs to ideally be a minimum of approximately 1.5 metres in order to allow the digger and mechanical dumper a passage to move through. It is possible with a smaller access point of approximately 1.0 metre but bear in mind that this will effect the whole project duration and will impact cost.

The average size pool, 10 x 4 metres, will require the excavation, transport and removal of approximately 90m3 of soil. In order for the construction to be streamlined and efficient, the distance from the pool location to the soil removal point and the machines used will need careful consideration as usually the soil will be removed from site via a grab lorry which will need space to manoeuvre.

Another factor is the storage of materials, the average pool will need 30 tonnes of materials to be delivered and moved to the construction area. In order to protect the surrounding environment, Origin will take the necessary steps and lay temporary protective pathways, construct access ramps and make things safe.

Pool Covers

Keeping your swimming pool clean and maintaining the equipment is essential for its longevity, a pool cover is the most important piece of equipment you can buy for your pool; they cut down on energy use and costs whilst saving you time and money in the long run.


The top 8 reasons why you should buy a pool cover:

  1. Stops evaporation - wondering why you have to keep topping up your pool? Every day your swimming pool is left uncovered, your pool water is slowly evaporating and a pool cover will help prevent this.
  2. Reduces chemical use - as helpful as pool chemicals are, they can cause allergic reactions if used too frequently. A pool cover will lessen the chemical use by up to 30%.
  3. Retain heat - covering a heated swimming pool when not in use will reduce heat loss, giving you warmer water. For a swimming pool that relies on the sun for heat, covering it at night can still make it warm enough to swim in the next day, instead of losing all the heat overnight when the temperatures drop.
  4. Keeps the pool clean - Simply having a cover on your pool will stop debris finding its way in, resulting in less hassle and cleaning for you.
  1. Cuts energy costs - pool covers will conserve your energy consumption whether your pool is heated with gas, electricity, a heat pump or solar.
  2. Saves money - it’s worth the investment, your heating bills will be lower, you’ll save on chemicals and cleaning and you won’t use as much water.
  3. Easy to use - an automatic pool cover can be used at the click of a button and the manual covers are just as easy.
  4. Safety - most importantly, swimming pool covers can save lives. A swimming pool is the ultimate venue for family fun so make sure everyone stays safe, even if your pool is fenced off, a pool cover will be the last layer of protection.

Swimming pool covers are an investment, there are multiple choices to fit every price limit so make sure you budget for the right style. We’ve put together a list of the pool covers we use with approximate pricing and merits (based on a 8m x 4m outdoor pool):

Manual Solar Bubble Cover - £1000 -£1430 - Poor safety, good heat retention, manual operation

Semi Automatic Foam Cover - £3500-£6000 - Average safety, excellent heat retention, easy to use

Automatic Slatted Surface Mount Cover - £8300-10700 - Good safety properties, excellent heat retention, very easy to use

Hidden Automatic Slatted Cover - £18-20,000 - Good safety properties, excellent heat retention, amazing aesthetics, extremely easy to use

Automatic Safety Cover - £21400-£23800 - Highest level of safety properties, excellent heat retention, very easy to use

Water Treatment Options

Water treatment is a fundamental requirement for swimming pool owners to ensure the water is free from harmful bacteria, viruses and algae. The water must not cause corrosion or scaling and it should not cause any discomfort to bathers. Bacteria, viruses and other micro-organisms are carried into the pool by swimmers and can multiply in untreated water. In order to ensure your pool doesn’t have these problems, a pool disinfectant must be used;


Chlorine is the top product used for treating swimming pool water. It is highly disinfecting, adapts to huge volumes, easy to use and most particularly, economic.

It can have disadvantages when used incorrectly or when the quantity is not respected: it may cause irritation. This is due to chloramine, a substance which is formed when chlorine interacts with the swimmers, particularly with their sweat, saliva and other secretions. It is this substance which causes skin, eye and respiratory irritations.

UV Ultraviolet

The principle is simple: A lamp which produces ultraviolet rays (UV-C rays), is placed in the filter circuit. When dirty water passes through the lamp, the rays destroy the DNA of micro-organisms. The water comes out treated… but not disinfected! For this, another type of treatment needs to be used alongside the lamp (chlorine) but in reduced strengths.


It is a common misconception that saltwater systems do not have chlorine. A saltwater pool will have lower levels of chlorine than a traditional chlorine pool as it’s produced at a steady level rather than added to the pool with chlorine sticks or tablets. Salt is added to the pool instead, and a saltwater generator produces hypochlorous acid for sanitation through electrolysis which is the breakdown of the salt by passing electricity through the saltwater solution. Despite the name of a saltwater pool, the salt content is approximately that of human tears, about one-tenth the salinity of ocean water. Swimmers can open their eyes underwater and it has the added benefit of making bathers skin feel softer.




Treating water with magnesium is based on 2 processes: on the one side, we have MagnaPool® minerals, made up of magnesium, which act as a water treatment, and on the other, a new filtering medium which must replace the existing one (containing pure glass crystals, called Crystal Clear®). This complete system allows for the enriching of the water in terms of minerals; it is thus healthier and more environmentally friendly. Studies have proven that absorbing magnesium chloride through the skin (transdermal) is one of the most effective ways for the body to maintain healthy levels of this important mineral. Magnesium is responsible for many important cellular processes in the body. It can support detoxification, reduce stress and alleviate aches. It promotes energy and wellbeing, and can restore soft and healthy skin. It will help keep chloramine levels to a minimum, so the water is gentler on sensitive skin. Due to the strong flocculent effect of magnesium, it works like a magnet helping to remove impurities, organic debris and combined chlorine.

Heating an outdoor pool

Gas Boiler

High performance gas boilers use natural gas, LPG or butane as the main fuel source.

  • Advantages:
  • Gas boilers are compact and occupy very little space.
  • Reduced emissions over oil boilers.
  • The heat source is always available, irrespective of weather conditions.
  • Rapidly heats pools.
  • Can provide an economic investment opportunity, especially if the existing boiler located close to the pool system.
  • Combines perfectly with alternative systems (i.e. renewable energy secondary systems).
  • Disadvantages:
  • Relatively high running costs when used as the sole heating source.
  • If there is no gas supply nearby, the connection costs can mount up.
  • NB: Propane (LPG) and butane solution

Oil Boiler

In a dedicated swimming pool oil heater, domestic fuel oil is burned, heating fluid in a closed loop to a high temperature. This fluid is circulated through a series of stainless or titanium tubes which come into contact with the pool water, heating it up as a result.

  • Advantages:
  • The same advantages as the gas boiler (above)
  • Disadvantages:
  • Relatively high running costs when used as the sole heating source.
  • Powered by fossil-fuels, so a high carbon footprint.
  • Costs are volatile and linked to crude oil pricing.
  • Deliveries required

Air Source Heat Pump

Heat pumps are a great alternative that will help you lower your carbon footprint and boast highly efficient performance ratings. They are becoming an ever increasing popular choice to heat swimming pools with.

  • How they work:
  • An air-to-water heat pump absorbs heat from the air and transfers it to the pool water. Natural energy from the surroundings is drawn into the heat pump by a large fan. This is initially absorbed by the heat pump’s first heat exchanger, known as the ‘evaporator’, which contains a highly conductive cold refrigerant liquid.
  • Another small pump is then used to circulate the energy around the heat pump, allowing the liquid to absorb heat energy from the air. As this happens, the liquid turns from a cold liquid into a cool vapour.
  • This cool vapour then passes through a compressor which squeezes it and significantly raises the temperature of the vapour. This now hot vapour passes through a pool water heat exchanger where the heat transfers to the pool water, heating it up. As it offloads its heat, the hot vapour condenses back into a cool liquid, before passing through an expansion valve to convert back into a cold liquid, and restarting the cycle.
  • Why they’re a great choice:
  • The most noteworthy feature of a heat pump is the fact that they can actually extract more heat energy than they consume during their operation.
  • Advantages:
  • Affordable system with a good return on investment compared with fossil fuel heating systems.
  • Superb ecological credentials, and suitable for achieving an entirely energy self-sufficient pool with photovoltaic panels.
  • Works using heat in ambient air, so it heats your pool even when the sun isn’t shining.
  • Water can be heated at night and utilise cheaper electricity night rates.
  • Disadvantages:
  • It is usually not possible to use a heat pump to heat the water to swim in the winter, as its efficiency diminishes when the temperature drops below 10°C.
  • The positioning of the unit which does emit mechanical noise can be a compromise.
The team at Origin have 40 years of experience specialising in the construction of indoor pools. We have architects experienced in everything from archaeological requirements through to listed buildings and conservation. Our construction specialists lay down the detailed design for each project to ensure your pool building is trouble free. Having built in excess of 1500 indoor pools it’s safe to say, we know what we’re doing and we’ll be there for you from concept to completion.

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