Waikato Regional Council’s Environmental Performance Committee has considered a comprehensive recent study by Massey University on our domestic drinking water supplies. The report confirmed that rivers draining agricultural catchments with cows, sheep and deer had a high prevalence of cryptosporidium, giardia, campylobacter and e- coli. Those draining native forest catchments had little if any pathogens.
The study concluded that there should be a limit to agriculture intensity and/or to utilise riparian vegetation buffers to help reduce the prevalence of pathogens in many waterways.
The study also pointed out that it was not safe to rely on conventional water treatment and chlorine disinfection as this was often ineffective. – eg. the Havelock North outbreak which caused four deaths and thousands of serious illnesses.
Managing the state of the raw water supply in the water supply catchment is therefore critical for ensuring a safe drinking water supply and avoiding potentially fatal disease outbreaks. This management is WRC’s responsibility.
A serious human health problem
New Zealand drinking water-related gastrointestinal illness has been estimated to be between 18,000-35,000 cases per year.
The Annual Report on Drinking Water Quality (2017–2018) by the Ministry of Health has a summary of compliance by local authorities in the Waikato Region.
The latest report for the 2018-2019 year published by the Ministry of Health in June 2020 is here
TCDC is not alone in this miserable failure – many other district councils have a similar poor record. There is no avoiding that this is a damning indictment of the management of our domestic drinking supplies by local district councils.
Serious reform is required
Thankfully that is now underway. There are currently proposals before Parliament to improve drinking water management and there are other relevant recent legislative changes.
There will now be a dedicated drinking water regulator, Taumata Arowai, and reform of the National Environmental Standard for Sources of Human Drinking Water (NES-DW).
WRC has a role primarily under the NES-DW in the protection of community drinking water supply source waters as part of a multi-barrier approach to ensure the provision of safe drinking water.
The major change in the current review of the NES-DW is a requirement for Regional Councils (RCs) to establish formal source protection zones (SPZs) for drinking water supplies.
Regarding the Water Services Bill (likely to be adopted in 2021), the most relevant requirements for WRC relate to source water. WRC must publish information on the quantity and quality of source waters and interventions to manage risk. WRC would also contribute to the development of source water risk management plans by suppliers by providing information on land-use activities and potential sources of contamination.
RCs must also establish formal source protection zones (SPZs) for drinking water supplies.: –
– SPZ 1 An immediate zone around the supply intake where land-use would be strictly controlled given contaminants could have direct impacts.
– SPZ 2 An intermediate zone, which for groundwater is principally designed to ensure microbial attenuation delineated by a travel time of 1 year. For surface waters this zone is delineated by an 8 hour travel time and would extend 100 m landward. Zone delineation would enable selected land-uses and discharges to be limited in this specific area.
– SPZ 3 This zone currently comprises the entire upgradient catchment. In this zone diffuse contamination, cumulative effects and sources of persistent contaminants may be managed.