Picton drinking water does not meet national standards and a resident says he's not surprised considering the "brown muck" left at the bottom of his water distiller.
Paul Beauchamp-Legg said he needed two bottles of white vinegar and four canisters of baking soda every two months to scrub the brown grime from his water filter, which he used daily.
He started filtering his drinking water to remove impurities and avoid the risk of getting giardia - a possibility at Picton's Speeds Rd water treatment plant.
The site does not comply with National Water Standards outlined in the Health (Drinking Water) Amendment Act 2007 because it does not use ultraviolet light to treat the water for microscopic parasites, such as giardia or cryptosporidium, which are typically carried in infected animal faeces.
"The water quality is shocking, the stuff on the bottom gets really hard - it's just incredible the amount of dirt that comes out," Mr Beauchamp-Legg said.
"It looks more like mud than anything else, but I don't know if there's excess chemicals in it."
He has filtered his drinking water for the past 10 years and cannot remember what unfiltered water tasted like to compare the two.
"A third of the town are superannuitants, so if they've got that far and they're drinking it, it can't be too bad," he joked.
National water standards require two key risks to safe water: bacteriological, which typically requires a site to use chlorine to kill escherichia coli, and protozoa, which involves scanning the water with an ultra violet light to kill giardia or cryptosporidium which cannot be eliminated by chlorine.
Picton residents get their water from a treatment plant at Essons Valley, which meets national water standards, and an aquifer at Speeds Rd.
Marlborough District Council operations and maintenance engineer Stephen Rooney said the Essons Valley treatment plant was upgraded to meet the standards last year because it posed a greater risk of water contamination, due to its open-air dams, as opposed to the Speeds Rd site which drew water from an aquifer, an underground gravel-filter system.
"We have not detected any levels of giardia or cryptosporidium.
"There is some risk that may be an issue if an animal pollutes the waterway and that defecation gets in to our supply.
"The greater risk was Essons Valley because it's a stream-fed catchment. The water at Speeds Road is filtered through gravel, so the risk is very much reduced - it's very, very low, but we've got to get it up to standard."
The Speeds Rd site would be upgraded to meet standards by next year, he said.
Ultra-violet lighting could be difficult to install because the water had to be very clear for it to work.
"We will have to meet that part by putting in additional treatment."
Giardia and cryptosporidium are microscopic parasites transferred through faeces which cause internal illness leading to diarrhoea, weight loss and vomiting and can last untreated for about a month.
Drinking water sources become contaminated when faeces containing the parasites are deposited or flushed into water.
Other sources include direct exposure to the faeces of infected humans and animals or eating contaminated food.
People who want to take extra precautions can boil their water for one minute to kill any parasites that may be present.
Blenheim was the only town in Marlborough to meet the standards test. This was due to the completion of the Central Water Treatment Plant in Blenheim last year.
Marlborough District Council's 2011-2012 annual report stated the average person used more than 600 litres of water per day, increasing to more than 1000 litres on peak days over the past year.
AT A GLANCE
Marlborough's drinking water supply
Location | NZ Drinking Water Standards met? | Adequate capacity?
Blenheim | Yes | Yes
Awatere | No, compliance required by 2014 but delayed | Yes
Picton | No, compliance required by 2014 | Not during peak usage
Havelock | No, compliance required by 2014 but delayed | Yes
Renwick | No, compliance required by 2014 but delayed | Yes
Riverlands | Yes to microbiological but no to aesthetic | Yes
Wairau Valley | No, compliance required by 2015 | Yes
*Dates for achieving compliance delayed due to seeking affordable solutions.
Information sourced from the council's 2011-2012 annual report.
- The Marlborough Express