The embodiment of nature's perfection
Water quality analysis: Mineral composition, pH, Total Dissolved Solids and Drinking Water Standards explained
Water quality analysis examines the mineral composition of water through key measures such as pH and Total Dissolved Solids (TDS). Water mineral testing reveals how geology shapes taste, stability and quality. Regular testing ensures compliance with drinking water standards while confirming the long-term mineral stability and taste profile.
Key takeaways:
- Water quality analysis measures mineral composition, pH, TDS and Total Hardness to assess quality and consistency.
- Water mineral profile is a result of how geology directly influences taste, texture and stability.
- Otakiri’s artesian source shows long-term mineral consistency supported by decades of testing.
- TDS and Total Hardness levels directly influence mouthfeel, flavour neutrality and food pairing performance.
- Regular testing provides assurance for safety, regulatory compliance and premium hospitality service.the texture and finish. But there is one element that is almost always overlooked, even in great venues: the water it is served with.
Artesian water is naturally sourced groundwater that flows from a confined aquifer, where it is held under natural pressure between layers of impermeable rock. As it moves slowly through underground geological formations, it undergoes natural filtration and develops a stable mineral composition shaped by the environment it has travelled through.
Water quality analysis examines this composition in detail through key measures such as pH, Total Hardness, TDS and mineral composition. Regular analysis supports compliance with drinking water standards while confirming the consistent quality and refined taste profile of a premium artesian source.
Because no two water sources are identical, variations in geology, depth and flow conditions directly influence mineral content and overall flavour profile. Structured mineral water testing is therefore essential to understand not only composition, but also consistency over time and compliance with drinking water standards.
In premium hospitality and food service environments, this consistency is particularly important.
Mineral balance influences taste neutrality, mouthfeel and how well water complements food. Independent laboratory water quality analysis ensures the water served today reflects the same quality, stability and sensory profile expected in every pour.
What is the difference between artesian, mineral or spring groundwater sources?
Artesian, mineral and spring water are often grouped together, but they are not the same. The combination of natural protection, geological filtration and measurable mineral balance makes artesian water distinct from many other groundwater sources.
Artesian water
Artesian water is groundwater sourced from confined aquifers deep underground between impermeable rock layers. Water is slowly filtered through these layers of rock, typically resulting in a stable mineral composition due to the limited surface exposure. Artesian water is under enough natural pressure to rise above the top of the aquifer. In the case of Otakiri, the pressure is enough to take it above the land surface and through the production well.
Mineral water
Mineral water is water from a spring that contains various minerals, such as salts and sulphur compounds. It is usually still but may be sparkling. I can be naturally above or below ground. If sourced above ground, it is susceptible to above ground activity.
Spring water
Spring water is groundwater that is discharged to atmospheric pressure. As such, it is susceptible to above ground activity.
The Otakiri Aquifer
The Otakiri Aquifer is a deep volcanic-hosted artesian system within the Matahina Ignimbrite, providing long-term stable groundwater flow and mineral characteristics.
The Matahina Ignimbrite is a volcanic ashflow sheet formed approximately 300,000 years ago from eruptions associated with the Haroharo Caldera in the Okataina Volcanic Centre, part of New Zealand’s northern Taupō Volcanic Zone.
Ignimbrite is created during major volcanic eruptions, when dense flows of ash, pumice, crystals and volcanic glass settle and solidify. In some locations, these deposits become welded and naturally fractured, creating favourable conditions for groundwater storage and movement. These geological characteristics can support deep aquifer systems with natural filtration properties.
Put simply, the Otakiri Aquifer is a deep underground water reserve located between approximately 160 and 300+ meters below ground within a unique volcanic geological formation.
At 222 metres beneath the ground, water travels through hidden fractures in the Otakiri Aquifer at an estimated rate of 66,010,000 litres per day, or 764 litres per second, where it is continually confined and pressurised. The water acts as a solvent that dissolves and carries essential minerals from its subterranean environment. Water stored within this confined system remains under natural artesian pressure, allowing it to rise to the surface more than 50 years later.
The Otakiri Aquifer has been rated as providing the deepest, highest quality groundwater in New Zealand. Since 1996, it has been the source of Otakiri New Zealand Artesian Water.
Mineral profile breakdown
Mineral profile analysis measures dissolved minerals in water and explains how geological interaction shapes taste, mouthfeel and overall drinking experience.
Water’s mineral profile refers to the measurable concentration of naturally occurring minerals dissolved in water, typically expressed as milligrams per litre (mg/L). Mineral profile analysis isn’t simply a technical exercise. It provides measurable insight into the sensory qualities of water and helps verify the consistency expected from a premium artesian source, such as Otakiri.
Water is imbued with minerals as it moves slowly through underground geological formations, interacting with the surrounding rock over time. In artesian systems, this process often occurs over extended periods within confined aquifers, where water remains protected and relatively stable. As a result, artesian water sources are frequently valued for the consistency of their mineral composition, with fewer short-term fluctuations than many shallower water sources.
The geological journey is important because minerals influence more than chemistry alone. They contribute to how water tastes, how it feels on the palate and how it performs alongside food. Water with elevated mineral levels may feel heavier or leave a more pronounced finish, while certain mineral balances can introduce sharper or slightly bitter characteristics.
By contrast, a balanced mineral profile is often associated with a cleaner, softer and more neutral drinking experience. In hospitality settings, this can be especially important where water is served with food, as a well-balanced composition is less likely to interfere with delicate flavours.
For a closer look at how these mineral characteristics affect dining experience, explore our guide to water pairing with food.
Understanding pH, TDS and water hardness
pH, TDS and Total Hardness are key chemical indicators used in mineral water testing to assess acidity, mineral concentration and Calcium/Magnesium content.
When assessing water quality, several core measurements help describe its composition and character. Three of the most referenced are pH, Total Hardness and TDS. While each measure something different, together they provide a more complete picture of water chemistry. pH indicates how acidic or alkaline the water is, Total Hardness measures the presence of calcium and magnesium that influence mouthfeel, scaling behaviour and mineral balance, and TDS reflects the concentration of dissolved minerals, salt and naturally occurring compounds present. Together these metrics help build a clearer picture of water composition, stability and overall drinking experience.
pH
pH measures how acidic or alkaline water is on a scale from 0 – 14, with 7 considered neutral.
A highly acidic water would have a pH level of 1, akin to battery or stomach acid, while an extremely alkaline water would have a pH of 14 similar to drain cleaner. In the middle, a pH level of between 7.0 and 7.5 indicates neutral taste and sometimes described as “sweet” because it is neither sour (acidic) or bitter (alkaline).
pH levels and the effect on taste
| pH level | Acidic or alkaline | Effect on taste |
|---|---|---|
| 1 | Acidic | Sour |
| 7 | Neutral | Sweet |
| 14 | Alkaline | Bitter |
Total Hardness
Total Hardness measures the concentration of dissolved calcium and magnesium in water. These naturally occurring minerals are dissolved as water moves through underground rock formations, making hardness an important indicator or geological origin and mineral composition.
In drinking water, hardness can influence mouthfeel, perceived texture and how rounded or smooth the water feels on the palate. Waters with lower hardness are often described as softer and lighter, while higher hardness levels can create a fuller, weightier drinking experience. Total hardness is also commonly referenced in technical water analysis because it can affect scaling behaviour, appliance performance and processing applications.
Impact of Total Hardness on water's taste and mouthfeel
| Total Hardness (as CaCo3 mg/L) | Classification | Typical taste and mouthfeel |
|---|---|---|
| 0 – 60 mg/L | Soft/low hardness | Light, smooth and clean with a softer mouthfeel |
| 61-120 mg/L | Moderately hard | Balanced texture with slightly more body and mineral presence, while remaining smooth |
| 121-180 mg/L | Hard | Fuller mouthfeel with a more noticeable mineral character and greater palate weight |
| 180+ mg/L | Very hard | Dense, pronounced mineral profile with a heavier texture |
Total Dissolved Solids (TDS)
TDS measures the combined concentration of dissolved minerals in water. It is measured in milligrams (a thousandth of a gram) per litre of water.
Lower TDS waters are generally perceived as lighter, cleaner and more neutral on the palate, while higher TDS waters often present a broader mineral character with greater weight and texture. For a more detailed breakdown of TDS ranges and how they influence flavour perception, see our guide to water taste and mineral composition. [link to blog 1]
Drinking water standards
New Zealand Drinking Water Standards define legal limits for water quality parameters, ensuring all drinking water sources meet safety and compliance requirements.
In New Zealand, the regulations governing potable water quality are set out in the New Zealand Government’s Drinking Water Standards. These standards establish the minimum acceptable levels for water to be considered safe and suitable for consumption, covering chemical, physical and microbiological parameters. They provide the benchmark used to assess water quality, purity and compliance across all registered drinking water supplies.
The standards set limits for the concentration of determinands in drinking water. Determinands refers to a substance or characteristic measured in drinking water. Each determinand is assigned a Maximum Acceptable Value (MAV) where relevant, representing the highest concentration permitted without posing an unacceptable risk to human health. Many of these limits are informed by guideline values developed by the World Health Organisation.
These requirements apply to all drinking water supplies, regardless of source type or population served. Whether water is drawn from an artesian aquifer, surface catchment or municipal network, suppliers must monitor quality against the applicable standards. Testing should be completed through accredited laboratories, with routine analysis used to verify that source water, treated water and final drinking water consistently meet regulatory requirements.
How water quality analysis ensures quality consistency
Regular water testing ensures consistency, environmental stability and compliance with drinking water regulations across all supply conditions.
Ongoing water testing is essential for ensuring both consistency and confidence in drinking water quality. Even when a source is naturally stable, regular monitoring confirms that key characteristics remain within expected ranges over time and that the water continues to meet established quality standards.
Consistency of quality
Routine testing helps verify that the mineral composition, pH and overall profile of the water remain consistent. For naturally sourced artesian water, this consistency is a key part of maintaining its distinctive taste and mouthfeel across time and batches.
Environmental and geological variability
While deep aquifers are generally well protected, factors such as the rock type in which the water is encased, rainfall patterns, recharge rates and surrounding land use can still influence water systems. Regular analysis ensures any potential changes are identified early and understood in context.
Adhering to standards
Testing provides ongoing confirmation that water remains compliant with drinking water standards, including chemical and microbiological safety parameters. This helps ensure that water remains safe for consumption at all times, not just point-in-time assessments.
Customer assurance
For restaurants and premium hospitality venues, water quality directly impacts beverage preparation and the customer experience. Consistent testing supports confidence in flavour neutrality, protects equipment from scaling issues and ensures a reliable foundation for food and drink service.
Our testing process and results
Otakiri’s long-term water quality testing confirms stable artesian composition with no harmful contaminants and consistent trace element balance over time.
We have been conducting scientific measurement and testing of water quality and chemistry sampling at Otakiri’s source for almost 30 years. In that time, the water mineral composition has remained consistent and shown high levels of stability.
Globally recognised testing and analysis by MWH, Eurofins Laboratories, Hills Labs and Beca verify that that Otakiri Aquifer produces naturally pure water imbued with an optimal combination of dissolved minerals that provides our water with its distinctive high-quality character and taste.
Testing results for Drinking Water Standards
Comparison between the organic compound analysis over consecutive tests and the Drinking Water Standards MAV for organic determinands of health significance, indicates there are no apparent organic compound contaminants present in the Otakiri bore water at levels of concern, with compounds being either below detection limit or well below the MAV.
Still water analysis
The secret behind our soft, beautifully balanced Otakiri water is the naturally occurring, optimal combination of critical trace elements.
Comparison of MWH/Eurofins 2011, BECA Hill Labs 2016/207, Hill Labs 2024 and Hill Labs 2025 testing results.
Note: Regulatory guidelines for 2024 and 2025 are DWSNZ
| Sample | Regulatory guideline | Result | Hills 2024 | Hills 2025 | % Difference |
|---|---|---|---|---|---|
| MWH / Eurofins 2011 BECA commissioned Hills 2016 /2017 | |||||
| a | b | c | (c-b)/b *100 | ||
| Bicarbonate (HCO₃) | DWSNZ | 39 mg/L 2017 | 40 | 40 | NIL |
| Calcium (Ca) Total ICAP | EPA | 3.4 mg/L 2011 | 4.0 | 3.8 | (5)% |
| Magnesium (Mg) Total ICAP | EPA | 2.0 mg/L 2011 | 2.2 | 2.1 | (4.5)% |
| pH units | DWSNZ pH 7.0 – 8.5 | 7.1 units 2016 | 7.0 | 6.9 | 1.4% |
| Reactive Silica (SiO₂) | DWSNZ | 72 mg/L 2016 | 74 | 74 | NIL |
| Sodium (Na) Total ICAP | EPA | 11 mg/L 2011 | 12.8 | 12.3 | (3.9)% |
| Total Hardness as CaCO₃ by ICP (calc) | EPA DWSNZ Hardness (calcium and magnesium) Less than 200 mg/L | 17 mg/L 2011 | 19.1 | 17.9 | (6.3)% |
| Total Dissolved Solids (TDS) | SM DWSNZ TDS less than 1000 mg/L | 140 mg/L 2011 | 127 | 120 | (5.5)% |
| Total Potassium (K) | DWSNZ | 3.6 mg/L 2016 | 3.9 | 3.9 | NIL |
Water may appear simple, but its quality is shaped by geology and chemistry. Laboratory water quality analysis helps reveal the mineral balance, taste profile and consistency that distinguish one source from another.
Supported by decades of water quality testing, Otakiri’s artesian water continues to demonstrate stable composition, natural purity and dependable quality. It is this combination of science and source integrity that defines exceptional water.
Frequently asked questions
What is water analysis?
Laboratory water analysis measures mineral composition, such as pH, Total Dissolved Solids (TDS), Total Hardness and trace elements to assess water quality.
Why does mineral composition matter?
Minerals influence flavour, mouthfeel, balance and how water pairs with food.
Is Otakiri water regularly tested?
Yes. Otakiri is professionally tested. Otakiri’s artesian source has undergone decades of laboratory testing to verify stability and compliance.
