Reports of business taking advantage of a popular chlorine-free water fill up for Christchurch residents.

Well water is available to the public at Cashmere's Siam Thai Day Spa, with a 25-cent a litre charge covering infrastructure costs after the first-litre.

But owner Duncan Laing says some people are taking huge quantities of water and not paying, including some businesses.

He claims they've seen tanker trucks pulling in and filling overnight, a coffee shop and restaurant are using their water, and a health shop is re-bottling the water and selling it on shelves.

He says businesses should be making enough money to buy their own water.

"There's got a bit of balance in life, and there's got to be a bit of fairness, and we'd just appreciate if people toed the line."

Laing says they're getting very close to closing the well down, but they want to keep serving the community.

"This is pretty much for the community, and we've limited the take to 60 metres a day per family but clearly there's more water going out snd that's not fair."

Laing says they're installing security cameras, and the water will now be available between 7am and 7pm.