The Auckland region has 14 Water Treatment Plants (WTPs) supplying 40 different distribution zones across the region. Some zones are supplied by just one WTP whereas others are supplied by up to four WTPs.
The composition of the water supplied from the majority of Auckland's WTPs is well suited to brewing and able to be adjusted through the addition of minerals and/or acid (or acidulated malt) to create water profiles for a number of different beer styles.
Whilst some distribution zones are supplied by up to four WTPs the mineral composition is similar enough to enable water adjustments to be calculated.
There are some WTPs that supply water that is not necessarily suitable for all styles or is not suitable for brewing at all.
The water supplied by the Bombay WTP, which supplies the Bombay distribution zone, has highly variable chloride levels fluctuating between 31ppm and 72ppm. This makes calculating water additions difficult. The sodium level of the water is also moderately high at 46ppm, which is fine for a number of beer styles and may help to enhance flavour, but may not be suitable when trying to brew a beer that is soft and delicate such as a Bohemian Pilsner or a Mexican Lager.
The water supplied by the Helensville WTP, which supplies the Helensville/Pakuranga distribution zone, also has highly variable chloride levels fluctuating between 20ppm and 66.5ppm. This makes calculating water additions difficult. The level of sulphate in the water averages 61.5ppm and the level of sodium averages 53ppm, which may may not be suitable when trying to brew a beer that is soft and delicate.
The water supplied by the Snells/Algies WTP, which supplies the Snells/Algies distribution zone has very high sodium levels (120ppm) and is not suitable for brewing. Sodium levels of more than 100ppm is likely to be above the taste threshold meaning beer made with the water may taste salty. This may however make the water suitable for brewing Gose.
Below are links to maps of Aucklands water distribution zones. Please use these maps to ascertain which source water to select when purchasing an ATF All Grain Brewing Kit.