Natural Swimming Pools

What is a natural swimming pool?

A natural swimming pool is a swimming pool that requires no chemicals. 

Using water flora and perennial plants, these swimming pools are cleaned naturally.

The goal of the natural swimming pool is to prevent the formation of algae, thus reducing the nutrients in the water, which helps to keep the water clear. 

A natural swimming pool also helps to control flood risks

How does a natural swimming pool work?

A natural swimming pool without chlorine can provide water quality above or equal to the community standards for bathing water.

Natural swimming pools depend on moving water or filters for heavy lifting.

The natural swimming pools are built with membranes or walls to keep the silt and soil out.

These pools can be converted from an in-ground pool that is existing or can be constructed from scratch.

To absorb phosphates and encourage good bacteria growth, natural swimming pools use biological filters like natural shale.

Good bacteria are promoted to reduce or discourage the growth of harmful bacteria and algae.

Adjacent to the swimming area, a ‘regeneration zone’ is constructed, filled with plant life.

These plants act as a natural filters and can also be used with a special pump for water filtration.

The water always flows around the plant life, preventing unwanted organic material from growing in the area.

In places where the climate is warmer, materials that act as natural filters are installed in the pool. Hydroponic plants also help in the filtration system.

Shapes of a natural swimming pool:

A natural swimming pool can be rectangular in shape or informally constructed on a levelled site.

They can be irregular in shape and are found along waterfalls, boulders, and rocks.

A shallow stone bed separates the filter bed and the natural swimming pool.

This band of stone should be between 100 and 200 mm in width.

Pros:

The number one reason you should consider a natural swimming pool over the chlorinated one is that they are chemical-free.

They create a natural habitat for wildlife and flora. It aids and supports plants, aquatic life, insects, amphibians, etc. 

Some microorganisms can also be found in these natural swimming pools that help to keep the water clean by consuming harmful bacteria. Plants like water lilies help the microorganisms by providing shade from the UV rays.

The roots of the plants can act as natural filters for excess contaminants and nutrients in the natural swimming pool.

The water quality is very high.

Plus, as no chemical filtration is involved in these natural swimming pools, the costs are less, and so are the requirements, though the initial investment for a natural swimming pool may be high.

These swimming pools can provide a luxurious style to the property.

Natural swimming pools can be custom-made as you want, and it is quite possible to build the entire pool yourself.

They are not restricted to a particular climatic condition.

They require very little maintenance and are eco-friendly.

The design is more adaptable and flexible when compared to traditional swimming pools.

Cons:

A large area of land is required to construct a natural swimming pool.

Though the maintenance cost is comparatively lesser, the initial price to build a natural swimming pool may be high.

It may not appear bluish as a traditional swimming pool.

The water may appear brownish as it is organic in nature.

The following steps are to be followed to build a natural swimming pool.

• Step-1: Dig the area on the ground
• Step-2: Zone the pool
• Step-3: Filtration
• Step-4: Sealing the natural swimming pool

Step-1: Dig the area on the ground:

Based on the depth of the pool needed, dig the area on the ground as a first step.

The pool can be shallow or deep, but the sides must slope to prevent the soil from caving in.

The ratio must be as follows: For every three horizontal feet, there must be a 1-foot vertical drop.

There is no need for any steel reinforcement in natural swimming pools.

Step 2: Zone the pool:

A minimum of 50 per cent of the pool’s surface area must be allocated for the shallow plants that can be cultivated either around the sides or at one end of the pool.

The plant zone and the swimming area must be separated using a rim that could be around 1 inch of the water’s surface.

The water from the swimming area moves to the plant zone for filtration.

The bacteria present in the plants’ fibrous roots serve as the biological filter and remove pollutants and contaminants from the water.

The plant’s roots also contain decomposer organisms that can eliminate the underwater waste buildup by consuming bacteria.

The water must go steadily deeper inside the plant zone, reaching a maximum depth of about 18 inches close to the swimming zone.

The submerged vegetation occupies the deeper area.

The shallow plant zone is home to many invertebrates that eat up the mosquito larvae while also using the zone as a breeding ground.

Step-3: Filtration:

Water circulation must be done continuously to clean the pool using plants’ roots.

The water has to be aerated, without which the pool could harbour anaerobic bacteria.

PVC tubes buried in the soil are recommended to channel the water to the plant zone.

At the bottom of the pool, diffused air is required, provided by underwater aeration.

Water circulation is done effectively, and the energy required is less in this type.

Using high-strength tubing and an air compressor, an aerator can be built.

Skimmers can be used to remove the floating detritus.

Step 4: Sealing the natural swimming pool

There are two ways to seal the natural swimming pool.

Bentonite clay: The first option is to apply bentonite clay to seal the soil. This clay bonds with the particles in the soil, thereby preventing the water from the pool from leaking into the ground. This clay acts as glue. In some cases, the earth has good clay; in these cases, just compacting the bottom of the pond will help hold the water. Talking to local pool builders would help. 

Bentonite could be directly applied to the soil in humid climates. But it is important to note that bentonite does not bond with dry surrounding soil or sandy soil. Before using bentonite on the pool, it is essential to compact the ground using a plate or a lawn roller. 2 to 3-inch layer of bentonite should be applied along the bottom and sides of the pool while wearing a mask. After that, another layer of topsoil and compact must be used.

Liner: In the case of a liner, instead of a PVC, EPDM(Ethylene Propylene Diene Monomer), which is a synthetic rubber, is preferred. It is expensive compared to PVC but is flexible during cold weather and offers protection from UV rays. In the case of sandy soils, a 30mm liner can be used. Whereas when the soil contains lots of roots and rocks, a 45 to 60mm liner would be required.

After applying a layer of either bentonite clay or liner, gravel of depth 4 to 5 inches should be applied at the bottom of the pool. This gravel that is to be used must be clean. A plate compactor could be run at the pool’s edges along the perimeter to assist with soil erosion. Wood planks, rocks, and flagstones can be used along the edges, or planting along the edges would help stabilise.

Concrete options:

Materials like cement or Rastra block could be considered when a conventional pool shape is preferred. Rastra block is a material manufactured from recycled foam plastic and cement. These are less eco-friendly than stone and gravel, but they help reduce the chemicals by a significant amount as they use plant-based filtration systems.

Because of the complexities involved in concrete pouring, it is not advisable to construct a concrete pool yourself, especially when you are not experienced in concrete work. When a Rastra block is used, a hole larger than the dimensions of the swimming pool is dug. The bottom of the pool is either covered using a rubber liner, or a concrete slab is poured. After that, the bottom layer is covered with gravel. A backflow preventer and a drain should also be installed. At the edges, one section of the Rastra block is laid. Using rebar, the Rastra is secured to the pad. The cavities of the Rastra block are filled with concrete. In between the courses, an expanding foam sealant is to be used. This is also used at all joints, which can help to hold the blocks. The space is backfilled with soil between the Rastra block and the pool sides. The perimeter along the pool’s edges can be laid using stones, or plants can be grown at the edges of the blocks.

After constructing the pool, allow it to rest for one week before plants are installed. 

The plant zone must be prepared using 3 to 6 inches of soil. This soil must be free of contaminants such as organic matter or animal excrement. A lab test for soil samples can also be conducted.

It is important to choose plants that are suited to the climatic conditions of your area. 

The best option would be to buy them from a native supplier of plants.

For emergent vegetation, along your pool’s perimeter, sedges and rushes which are both aquatic plants might be a great option.

It is also important to choose plants in such a way that one does not overcrowd the other.

Aquatic irises and lesser cattails could also be considered. 

In areas of the pool where water is shallow, consider Pickerelweed, water primroses, and arrowhead.

Owing to their high output of oxygen, submergent plants such as the hornwort and common waterweed could also be some of the best options.

In areas where water is 6 to 18 inches deep, consider a mix of submergent, emergent, and floating plants. 

Consider water lilies that can be suitable for any depth. 

For floating plants, consider common duckweed and pondweeds.

It is important to be mindful of the laws protecting wetlands, before proceeding to collect plants from the wild.

Natural swimming pool builders

Some of the best natural swimming pool builders in Europe are as follows.

1. Alba Pools: Alba Pools is a Scotland-based swimming pool construction company specialising in pools and spas. They also supply swimming pool accessories and equipment. Check them out in alba-pools
2. Falcon Pool: One of Europe’s top 50 companies in swimming pool construction. They are experts in building standard and customised swimming pools. Check them out herein falconpools
3. Albixon: Albixon is reputed for its Albistone pools that can be rectangular, oval, round, sharp-cornered rectangle, or atypical pool designs. They also offer swimming pool accessories. Check them out in albixon
4. Tanby Pools: Tanby Pools provides customised swimming pool design solutions, be it a simple swimming pool or high-end or luxury, based on the customer’s needs. Check them out in tanbypools
5. RivieraPool Fertigschwimmbad GmbH: RivieraPool Fertigschwimmbad GmbH, based in Germany, produces equipment known for its durability. The main swimming pool designs are MLine, Style-series, classic, and D-Line. Check them out in rivierapool
6. Jetform Swimming Pools: Jetform Swimming Pools offer pool construction, spa sauna, service maintenance, and pool refurbishment. They provide affordable and quality accessories and pools. Check them out in jetformpools.
7. Piscine-Plus: Piscine-Plus offers pool renovation services, above-ground swimming pools, spas, and security accessories. They are known for their Christal Pools which are uniquely shaped. Check them out in piscine-plus.
8. Pebble Pools: Pebble Pools – a pioneer of “the pebble pool” concept in Portugal and Europe specialising in freeform pools, traditional pools, razor-edge & combination pools, and natural rock pools. Check them out in pebblepools
9. Roman Pools: Roman Pools has over 25 years of experience in the swimming pool market. They are known for their quality workmanship. Check them out in romanpools
10. Compass Ceramic Pools UK: Compass Ceramic Pools UK – pioneers of composite ceramic swimming pools. They have constructed more than 30,000 pools on a global level. From indoor to outdoor pools, they have got it all covered. Check them out in .compass-pools.

Cost of building a natural swimming pool

The construction of the natural swimming pool, the size, and type required, including the features and many other factors, play a significant role in deciding the cost of the natural swimming pool.

A natural pool of size 40 m2 incorporating a swim zone of 20 m2 starts somewhere at £40,000.00 plus Vat.

A natural pool of size 100 m2 incorporating a swim zone of 50 m2 starts somewhere at £65,000.00 plus Vat.

A bespoke natural pool of size 200 m2 incorporating a swim zone of 80 m2 starts somewhere at £100,000.00 plus Vat.

Examples of natural swimming pool

1. This natural swimming pool is 30FT x 40FT and 20,000 gallons approximately. It contains an underwater wooden wall, a central swimming area, a rainwater collection system, and a step-in pebble beach. This natural swimming pool was built with concrete.

2. This 300 m2 Radwinter natural pool consists of a filter bed stream that runs right from below a glass bridge and false brick to jetties and stepped shallow areas through to a wide round pond.

3. This natural beauty, part of the garden with clean water free of chemicals like chlorine is absolute bliss.

4. Take a look at this amazing natural swimming pool!

5. 90FT x 70FT, more than 200,000 gallons contains granite boulders, pier and stream with bridge, a zero-entry pebble beach, and waterfall.

6. This 60 m2 pool is known for its small geometric designs in an informal setting.

7. “It is so much more than a pool area could be – a place for wildlife and beautiful insects, like Emperor dragonflies; a place to work and just think about things.” – gartenart

8. This natural swimming pool is a 12-foot deep, spring-fed natural swimming pool. It contains a waterfall with a hidden grotto, an 18-foot custom waterslide, and a gentle-entry pebble beach.

9. This 350 m2 natural swimming pool was built by half raising the ground and half digging. This pool has been designed to cope up with a temperature of -30 degrees celsius in winter. It is also very much used in temperatures of +30 degrees celsius when a meter of ice has melted.

10. This natural swimming pool is about 35FT x 60FT and 98,000 gallons approximately. It consists of hot springs, a waterslide, a step-in pebble beach, and an artificial jumping rock.

Planning Permission:

Conventional swimming pools and natural swimming pools and ponds are included in the same category.

The most up to date regulation from the Town and Country Planning Act 2015, Part 1, Class E stipulates that a client will generally not need planning permission if you meet these key requirements (there are others, but these are the main ones):

• The property is not listed, and
• The site is within the curtilage of the property, and
• You are not in an Area of Outstanding Natural Beauty (AONB)

Planning permission will be required if:

• Your property is listed
• You want to build on agricultural land