The pH scale measures how acidic or alkaline a substance is, with 7 being neutral. Water with a pH above 7 is alkaline, or basic, and higher numbers indicate stronger alkalinity. While swimming in slightly elevated pH water is tolerable, the risk of discomfort and tissue damage increases significantly as the level rises. High pH water reacts with the body’s naturally acidic protective layers, causing irritation and potential injury.
Defining the Safe and Unsafe pH Range
The ideal range for swimming water comfort and safety is slightly alkaline, falling between a pH of 7.2 and 7.8. This range promotes effective sanitation while remaining gentle on human tissues. Within this optimal window, the water’s pH closely matches that of the human eye, minimizing irritation.
When the pH level climbs above 7.8, it causes mild irritation, leading to dry skin and itchy, red eyes. This elevated alkalinity also dramatically reduces the effectiveness of chlorine sanitizers, potentially leading to the proliferation of bacteria and algae. As the level continues to rise, the potential for discomfort and equipment damage increases.
The threshold for immediate and severe danger lies at a pH of 12.5 and above, classifying the water as corrosive hazardous waste. While pool water rarely reaches this extreme, any reading above 8.5 should be addressed immediately. This prevents discomfort and protects pool infrastructure from scaling. Even a small increase in alkalinity beyond the ideal range can multiply the potential for adverse effects.
How Alkaline Water Affects Skin, Eyes, and Hair
Alkaline water interacts negatively with the body by disrupting its natural protective barriers, which are slightly acidic. Healthy human skin maintains an “acid mantle” at a pH of approximately 5.5, guarding against bacteria and environmental stressors. High pH water strips this natural acidity, leaving the skin dry, itchy, and vulnerable.
Exposure to highly alkaline water can exacerbate symptoms for individuals with existing skin conditions, such as eczema or dermatitis. The continuous loss of the protective mantle causes the skin to lose moisture more easily, which results in uncomfortable dryness after swimming in unbalanced water. This corrosive effect makes even moderately high pH levels a concern for frequent swimmers.
The eyes are the most vulnerable part of the body to high pH exposure. Unlike acid burns, which are typically surface-level, alkali burns penetrate deep into the eye tissue, causing extensive damage. High pH water causes immediate and severe irritation, leading to redness and stinging as the eyes’ natural buffering mechanisms are overwhelmed.
Alkaline water also affects hair health by raising the outer layer of the hair shaft, known as the cuticle. When the cuticle lifts, the hair becomes highly porous, leading to moisture loss, frizziness, and a dull appearance. This open cuticle structure also allows hair dye to escape more easily, accelerating the fading of color-treated hair.
Navigating High pH in Pools and Natural Water
High pH water is encountered in two main settings: treated swimming pools and certain natural water bodies. In pools, alkalinity often rises due to the addition of common sanitizers or the use of certain chemicals, quickly pushing the pH above 7.8. Natural sources, such as mineral springs or alkaline lakes, have high pH due to the concentration of dissolved minerals.
Pool maintenance requires regular testing to keep the water balanced, ensuring the pH remains within the 7.2 to 7.8 range. If the pH is too high, pool operators use chemical additives called pH reducers or pH minus products. The most common reducers are liquid muriatic acid or the granular alternative, sodium bisulfate (dry acid).
If severe exposure to high pH water occurs, especially in the eyes, immediate first aid is necessary. The injured person should flush their eyes continuously with clean, lukewarm water for at least 15 to 30 minutes. It is important to hold the eyelids open during the rinse to ensure the water reaches all parts of the eye. Seek immediate medical attention, bringing information about the chemical involved if possible.