The Vigilance and Anti-Corruption Bureau (VACB) on Friday said that water delivered in private tankers to homes, hotels, flats and other establishments in the city might always not be of potable quality and hence, posed a grave risk to public health.

A team led by Superintendent of Police E. Sherifudeen and Circle Inspector B. Reji Kumar had conducted a random assessment survey of the quality of water sourced by private water tanker companies, ostensibly from the Kerala Water Authority’s (KWA) water purification plant near Aruvikkara dam, and sold to private parties at “several times” the government price of Rs.300 for 1,000 litres.

Investigators said they had inspected the premises of a prominent private tanker company at Vazhayila on the outskirts of the city. They said they found scores of tankers filled with water parked in the large compound.

On a telephone call, the company would send their water-laden tankers to clients.

Most of the callers at the time of inspection were hoteliers, residents, and private hospitals. The company branded their supply as “drinking water”.

On inspection of records, the VACB said it found that the water in the tankers had been filled from the Aruvikkara plant at least a week before. The stagnation in the closed iron tank had degraded its quality and rendered it unfit for human consumption, investigators said.

The VACB collected the water samples in the presence of an independent government witness and despatched them to a State-owned laboratory for verification.

The VACB also said it found that certain tanker companies delivered less than 5,000 litres of water to their clients but charged for double that quantity. Consumers had no way of measuring the quantity of water delivered and had to trust the word of the suppliers, investigators said.

The ‘tanker mafia’ had dominated the supply of water to water-scarce areas in the district so much during the summer months that the public relied more on the companies run by the racketeers than the KWA directly for potable water supply. Investigators said they suspected that the racketeers sold untreated well water as purified drinking water to clients.

The VACB said that tankers contracted by the Revenue Department to supply water to scarce regions often illegally diverted part of it to private parties.