Share this story, choose your platform!
More and more pool owners are asking about a freshwater swimming pool. The idea is simple and appealing: water that feels soft and natural, without the strong chlorine smell, red eyes or dry skin that many people remember from public pools. But “freshwater” is used in a few different ways, and it is worth knowing exactly what it means before you choose a system for your own home.
This guide explains what a freshwater pool is, the main ways of achieving one, how they compare with traditional chlorine and saltwater pools, what they cost to run and what to ask before you decide. Whether you are planning a new pool or thinking about changing the water treatment in an existing one, it should help you understand the options.
What is a freshwater swimming pool?
There is no single official definition of a freshwater pool. In everyday use, it usually means one of two things:
- A low chemical pool, where a conventional pool uses modern treatment systems, such as UV, ozone or mineral systems, so it needs far less chlorine than usual.
- A natural swimming pool, where the water is cleaned by plants, gravel and biological filtration instead of chemicals.
Both aim for the same result: clear, healthy water that feels closer to swimming in a clean lake than in heavily chlorinated water. The way they get there, and the way they look, are quite different.
It is also worth clearing up one common confusion. A freshwater pool is not the opposite of a saltwater pool in the way that a lake is the opposite of the sea. A saltwater pool contains only a mild level of salt, which a chlorinator turns into chlorine. Our guide to the saltwater pool explains how that works.
Why people choose a freshwater pool
The reasons are usually about comfort, health and the overall swimming experience.
Gentler on skin, eyes and hair
High levels of chlorine and the by-products it creates can irritate skin and eyes and dry out hair. Reducing the amount of chlorine in the water makes swimming more comfortable, particularly for children, people with sensitive skin and anyone who swims every day.
Less chemical smell
That strong “swimming pool smell” is not actually caused by clean chlorine. It comes from chloramines, which form when chlorine reacts with sweat, skin cells and other contaminants. Systems that break these down, or reduce the need for chlorine in the first place, leave the air around the pool fresher. This matters even more for indoor pools.
A more natural feel
Many owners simply prefer water that feels soft and natural. For a pool in a garden setting, a freshwater approach can feel more in keeping with the surroundings.
Easier handling of chemicals
Using fewer chemicals means storing, handling and adding less of them. That is safer and more convenient, although some chemical care is still needed with most systems.
How to achieve a freshwater pool
There are several ways to reduce or remove chlorine from the water. They are often combined, because each one does a slightly different job.
UV treatment
Ultraviolet treatment passes the pool water through a chamber where a UV lamp kills bacteria, viruses and algae spores and breaks down chloramines. Because so much of the work is done by the UV unit, the chlorine level in the pool can be kept much lower. Read more in our guide to pool UV systems.
Ozone treatment
Ozone is a very powerful oxidiser. An ozone generator treats the water as it passes through the plant room, destroying organic contaminants and improving water clarity. Like UV, it works inside the plant room rather than in the main body of water, so a small amount of chlorine or another residual sanitiser is still needed to protect the water in the pool.
Mineral systems
Mineral systems release small amounts of minerals, such as copper and silver, into the water to help control bacteria and algae. They are designed to work alongside a reduced level of chlorine rather than replace it completely, and the mineral levels need to be monitored.
Advanced filtration
Better filtration removes more of the fine particles and organic matter that chlorine would otherwise have to deal with. Modern filter media and well designed circulation mean cleaner water with less chemical demand.
Natural filtration
In a natural swimming pool, the water flows through a separate regeneration zone planted with aquatic plants, along with gravel and biological filters. Beneficial bacteria and plants take up the nutrients that algae need, keeping the water clear without chemicals. These pools look more like a beautiful garden pond than a traditional design.
Freshwater, chlorine or saltwater: how do they compare?
Every approach has its strengths. Here is a simple comparison of the main options.
- Traditional chlorine pool: proven, effective and familiar. Needs regular chemical dosing and testing, and higher chlorine levels can affect comfort.
- Saltwater pool: a salt chlorinator makes chlorine from mildly salty water, so you handle fewer chemicals. The water feels softer, but it is still a chlorinated pool.
- Low chemical freshwater pool: UV, ozone, minerals and good filtration do much of the work, so chlorine can be kept to a low level. Comfortable water with a familiar pool look.
- Natural swimming pool: no chemicals at all, with plants and biological filtration keeping the water clean. A very different look, more space needed for the planted zone, and the water will not be as crystal clear or as warm as a conventional pool.
What does a freshwater pool cost to run?
The running costs of a freshwater swimming pool depend on the system you choose and how the pool is used.
UV and ozone systems use electricity to run and need occasional maintenance, such as replacing UV lamps. On the other hand, they reduce the amount of chlorine and other chemicals you buy. Mineral systems need replacement cartridges or electrodes from time to time. Natural pools avoid chemical costs altogether but need their planted areas looked after, and they are usually larger overall.
The biggest factor in most pool running costs is still heating. A good pool cover, an efficient heat pump and a well designed plant room make far more difference to your bills than the choice between treatment systems.
Is a freshwater pool right for you?
A freshwater approach suits many pools, but it is worth thinking about a few questions first.
How will the pool be used?
A family pool used most days in summer has different needs from a pool used for early morning lengths or an indoor pool used all year round. Heavier use means more contaminants for the system to deal with.
Indoor or outdoor?
Indoor pools benefit greatly from reduced chloramines, because the air around the pool is enclosed. Outdoor pools face leaves, pollen, rain and sunlight, which all affect water treatment.
How much maintenance do you want?
Nothing is maintenance free. Even low chemical systems need water testing, balancing and occasional servicing. Natural pools need regular care of the planting and filters.
What look do you want?
If you want a crisp, blue, architectural look, a low chemical system in a conventional design is likely to suit you. If you love the idea of a wild, planted swimming pond, a natural pool may be the answer.
Common myths about freshwater pools
Because “freshwater” is a loose term, a few myths come up again and again. Knowing the facts makes it easier to compare systems fairly.
“Freshwater means no maintenance”
Every installation needs looking after. A freshwater system reduces the amount of chemicals you add, but the water still needs testing, the pH still needs balancing and the equipment still needs servicing. What changes is the type of care, not whether care is needed.
“Red eyes are caused by too much chlorine”
Red, stinging eyes are usually caused by chloramines and poorly balanced pH, not by clean, correctly dosed chlorine. This is one reason why UV and good water balance make such a difference: they tackle the cause rather than simply adding more chemicals.
“Freshwater pools cannot be heated”
Low chemical pools can be heated just like any other conventional design. Natural pools are different, because warm water encourages algae and the planted zone works best at cooler temperatures, so they are usually left unheated or only gently warmed.
“It is only for new pools”
While planning at the design stage is ideal, many existing pools can be upgraded with UV, ozone or better filtration. The size of the plant room and the condition of the pipework usually decide what is possible.
Getting the water right from the start
The easiest time to plan a freshwater system is at the design stage. The plant room can be laid out with space for UV or ozone units, the filtration can be sized properly and the circulation can be designed so that every part of the pool is treated well.
Existing pools can often be upgraded too. Adding a UV unit or improving filtration is a common way to reduce chlorine in an established installation. Whatever system you choose, good water balance is still essential. Our swimming pool maintenance guide covers the basics of keeping water healthy.
Freshwater swimming pool at a glance
- What it means: usually a low chemical pool using UV, ozone, minerals and good filtration, or a fully natural pool cleaned by plants.
- Main benefits: softer water, less chlorine smell, gentler on skin and eyes, fewer chemicals to handle.
- Still needed: water testing and balancing, and in most systems a low level of residual sanitiser.
- Running costs: electricity and occasional parts for treatment systems, offset by lower chemical use. Heating remains the biggest cost.
- Best planned: at the design stage, although many existing pools can be upgraded.
Frequently asked questions
Is a freshwater pool completely chlorine free?
A natural swimming pool can be. Most conventional freshwater pools still use a small amount of chlorine or another residual sanitiser, because UV and ozone treat the water in the plant room but do not stay active in the main body of water. The level is simply much lower than with traditional treatment.
Is a freshwater pool safe to swim in?
Yes, when it is properly designed and maintained. Safe water depends on good treatment, good circulation and regular testing, whichever system you choose.
Is a freshwater pool the same as a saltwater pool?
No. A saltwater pool uses a chlorinator to turn a mild salt solution into chlorine, so it is still a chlorinated pool. A freshwater pool aims to reduce or remove chlorine altogether.
Can I convert my existing pool to freshwater?
Often, yes. Adding UV or ozone treatment, upgrading the filtration or fitting a mineral system can all reduce the amount of chlorine you need. A pool specialist can check what your plant room and pipework can accommodate.
Will a freshwater pool stay clear?
A well designed freshwater pool should have beautifully clear water. Natural pools are the exception: their water is clean and healthy, but it has a more natural appearance and can vary through the seasons.
Talk to HiLife Pools
Choosing the right water treatment is one of the most important decisions in designing a pool, because it shapes how the water feels every time you swim. HiLife Pools designs and builds beautiful pools for homes across the UK, and our team is happy to talk through the options for yours.
Get in touch with the HiLife Pools team to talk about your pool, or explore our pool designs and projects.
