Key Swimming Pool Terminology: A Complete Guide for Homeowners
Understanding swimming pool terminology helps homeowners make informed decisions about pool design, construction, refurbishment and long-term care. This glossary explains the most commonly used terms in modern swimming pool systems, written in clear, accessible language that reflects current industry standards and best practices.
Whether you’re planning a new pool or upgrading an existing one, these definitions will help you navigate technical conversations with confidence.
Acid: A substance that lowers pH levels in pool water. If pH becomes too low, water can turn corrosive, damaging tiles, grout, metal fittings and equipment. Balanced pH protects both swimmers and the pool system.
Algae: Microscopic organisms that thrive in warm or poorly balanced water. Algae cause cloudy water, slippery surfaces and staining. Correct circulation, filtration and sanitisation prevent growth.
Algaecide: A supplementary treatment used to prevent or slow algae formation. It supports sanitisation but does not replace chlorine, UV or ozone systems.
Alkalinity: The water’s buffering capacity, which helps stabilise pH levels. Correct alkalinity prevents rapid pH swings, cloudy water and scale build-up.
Bacteria: Micro-organisms introduced by swimmers or the environment. Without sufficient sanitisation, bacteria can multiply quickly and make water unsafe.
Backwash: A process used with sand or AFM® glass media filters, where water flow is reversed to flush out trapped debris and restore filtration efficiency.
Balanced Water: The correct relationship between pH, alkalinity, sanitiser levels, calcium hardness and temperature. Balanced water protects pool finishes, equipment and swimmer comfort.
Bather Load: The number of swimmers using the pool at one time. Higher bather loads place increased demand on filtration, circulation and sanitisation systems.
Basement (also known as subterranean Pools): Pools built below ground level, typically within basements. These installations require specialist waterproofing, structural engineering, ventilation and dehumidification.
Bespoke Pools: Custom-designed pools tailored to individual requirements, including size, shape, finishes, features and technology.
Booms: Movable walls that divide a pool into sections, allowing multiple uses within the same water body.
Bucket Test: A simple method for identifying water loss by comparing evaporation inside a bucket with water loss from the pool itself.
Chlorine: The most widely used pool disinfectant. It is most effective when pH is correctly balanced. Too much chlorine can irritate, while too little allows bacteria to grow.
Cleaners (Chemical & Robotic): Chemical cleaners maintain water hygiene, while robotic or manual vacuums remove debris from pool floors and walls.
Coping: The stone or tile edge that finishes the pool perimeter, providing a clean architectural detail and safe transition to the surrounding area.
Control Panel (Pool Automation): The system used to manage heating, filtration, lighting, dosing, covers and water features. Many modern pools use app-based automation for remote control and monitoring.
Counter-Current Units: Systems that generate a strong flow of water to swim against, ideal for fitness training in compact pools.
Covers: Pool covers help retain heat, reduce evaporation, cut energy use and keep debris out. Automatic slatted covers also improve safety and ease of use.
Dehumidifiers: Essential for indoor pools. Dehumidification systems control humidity levels, prevent condensation and protect the building structure.
Design & Build: A comprehensive service covering design, engineering, plant specification and construction.
Learn more about LSPC’s approach to pool design and construction in this award-winning energy-efficient pool project, which demonstrates how thoughtful design can improve performance and reduce running costs.
Electric Heaters: Simple heating systems typically used for small pools or spas. Less energy-efficient than modern heat pump solutions.
Electrical Design: The engineered layout of all electrical components, including pumps, lighting, ventilation, heating and safety systems.
Filtration: The process that removes debris and fine particles from pool water. Modern systems often use AFM® glass media for improved clarity and efficiency compared to traditional sand.
Interior Finishes: Materials lining the pool interior, such as tiles, mosaics, render, liners or stainless steel. Each finish affects durability, maintenance requirements and water colour.
Exterior Finishes: The materials surrounding the pool, including paving, decking and wall finishes, which define the overall aesthetic of the pool environment.
Fittings: Components such as drains, skimmers, jets and inlets that control circulation and water flow.
Flocculant: A product that binds very fine particles together so they can be filtered or vacuumed out, improving water clarity.
Ground-Source Heat Pumps: Highly efficient heating systems that extract heat from the ground. They offer stable performance but require specialist installation.
Heating Systems: Systems used to maintain comfortable pool water temperature. Air-source heat pumps are now the most energy-efficient option for most residential pools.
For a real-world example of efficient heating design, see LSPC’s energy-efficient swimming pool case study.
Hot Tubs / Spas: Small heated pools fitted with hydrotherapy jets, designed for relaxation, recovery and wellbeing.
Hydrotherapy: The therapeutic use of warm water to relieve pain, improve circulation and support rehabilitation.
Infinity Pool: A pool designed so water flows over one or more edges, creating the illusion of merging with the surrounding landscape.
Inground Pool: A permanent pool built into the ground using concrete, stainless steel or prefabricated structures.
ISPE: The Institute of Swimming Pool Engineers, providing professional education, training and technical standards.
Jets: Pressurised water outlets used for massage, hydrotherapy or water movement.
Landscaping: Garden and external design elements that enhance the setting and visual impact of an outdoor pool.
Level-Deck Pool: A pool where water overflows evenly into a surrounding channel, creating a sleek, mirror-like surface.
Lighting: LED and RGBW lighting systems used above and below water to enhance safety, ambience and architectural impact.
Liners: Vinyl membranes forming a smooth interior surface. Reinforced liners offer durability and a high-quality finish.
Maintenance: Routine care including cleaning, water testing, filter maintenance and equipment checks.
Moving Floors: Mechanised floors that allow pool depth to be adjusted or raised to deck level, enabling flexible use of the space.
Natural Pools: Pools filtered using plants and biological systems instead of chemicals. These require specialist ecological design.
Opening the Pool: Preparing an outdoor pool for the season by removing covers, cleaning, refilling and rebalancing water chemistry.
Ozone Systems: Water treatment systems that use ozone gas to oxidise contaminants and enhance water clarity, often alongside chlorine or UV.
pH Level: A measure of how acidic or alkaline pool water is. Balanced pH ensures swimmer comfort and effective sanitisation.
Plantroom: The operational heart of the pool, housing pumps, filters, heaters, dosing systems and control panels.
Pumps (Variable-Speed): Circulate water through the filtration and heating systems. Variable-speed pumps significantly reduce energy consumption.
Purification Systems: Technologies such as UV, ozone and automated dosing systems that support water hygiene.
Pool Hall: The enclosed environment around an indoor pool, requiring controlled temperature, airflow and humidity.
PWTAG: The Pool Water Treatment Advisory Group, which provides authoritative UK guidance on safe pool water management.
Quiet Pumps: Low-noise circulation pumps designed for energy efficiency and quiet operation.
Refurbishment: Updating an existing pool with new finishes, modern plant, improved heating or upgraded technology. If you’re considering improvements, see LSPC’s Ultimate Guide to Transforming Your Pool Parts 1, 2 & 3), which explains how refurbishment can enhance performance and longevity.
Safety Systems: Includes covers, alarms, non-slip surfaces, compliant electrics and correct chemical balance to protect users.
Sanitisation Systems: Chlorine, bromine, UV, ozone and automated dosing systems that maintain safe swimming conditions.
Sauna: A heated timber room designed for relaxation and wellness, often paired with pools or spas.
Servicing: Professional inspection and maintenance of pool equipment, water chemistry and plantroom systems.
Shock Treatment: A temporary increase in chlorine levels to break down contaminants and restore water clarity.
SPATA: The Swimming Pool & Allied Trades Association, which sets standards for best practice within the UK pool industry.
Stainless Steel Pools: Pools built with stainless steel interiors, offering a contemporary appearance, durability and low maintenance.
Steam Rooms: Enclosed wellness spaces using moist heat to create a warm, humid environment for relaxation and therapeutic benefit.
Test Kits: Used to measure pH, chlorine, alkalinity and other key water parameters.
Tile Finishes: Glass, ceramic, porcelain or stone tiles used to create a durable and visually striking pool interior.
Underwater Lighting: LED lighting installed within the pool structure to enhance atmosphere and visibility.
UV Systems: Ultraviolet systems that neutralise bacteria and chloramines, reducing reliance on chemicals.
Vacuums: Manual or robotic cleaners that remove debris from pool floors and walls.
Water Evaporation: Natural water loss caused by heat, dry air or ventilation. Excessive loss may indicate a leak.
Water Features: Decorative elements such as waterfalls, fountains and deck jets that enhance visual appeal.
Water Level: The height of water within the pool. Maintaining the correct level ensures effective filtration and skimming.
Windows (Acrylic Panels): Clear viewing panels integrated into pool walls, often used in luxury residential and commercial pools.
Whether you’re planning a new pool or refining an existing one, understanding the terminology helps you make informed choices and get the very best from your investment. London Swimming Pool Company can help you; not only choose, design, and build the best solution for your needs, but can also provide a qualified pool engineer to maintain and service it. Get in touch by calling us on 020 8605 1255 or email us.
