Colour is organic material that has dissolved into solution, while turbidity consists of tiny particles suspended in the water column. If a glass of water were left on the counter overnight, in the morning the material causing turbidity would have settled to the bottom of the glass while the colour would remain as before.
It is the organic material in the watershed that causes both colour and turbidity. While colour and turbidity are present at low levels for most of the year, they are particularly visible during spring runoff (May - June). This is caused by high flows from the lower elevation snow pack flowing into the creek. the melting snow causes the creek to rise and wash tiny particles of clay, silt, organic and inorganic matter, plankton, and other microscopic organisms into the District's intake. The smaller particles pass through our screens, are disinfected with chlorine, and enter the distribution system.
Turbidity is a critical parameter in drinking water because bacteria, viruses and parasites can attach themselves to the suspended particles. In addition, particles in turbid water can interfere with disinfection by shielding contaminants from the disinfectant. The water is treated with sufficient amounts of chlorine to ensure that an adequate chlorine residual remains in the water to effectively disinfect any pathogens that may be present.
Spring Runoff occurs annually April to June. Water that looks dirty can be expected but is still safe to drink. You may choose to leave your drinking water in the fridge to allow it to settle.A check of your household water filters during this time would be advised as extra fine filters cannot cope if silt is present.
Good (<1 NTU) - It is recommended that newborns and people with compromised immune systems drink boiled water or a safe alternative.
Fair (1-5 NTU) - It is recommended that children, the elderly, people with compromised immune systems and anyone seeking additional protection drink boiled water or a safe alternative.
Poor (>5 NTU) - It is recommended that all users drink boiled water or a safe alternative. Tap water intended for drinking should be brought to a rolling boil for at least one minute.
How is turbidity measured and reported?
Turbidity, which is measured and reported in nephelometric turbidity units (NTU), is an optical measurement of water's ability to scatter and absorb light rather than transmit it in straight lines. Turbidity levels can range from less than 1 NTU to more than 1,000 NTU. At 5 NTU water is visible cloudy; at 25 NTU it is murky.
How often is my water tested, and for what?
Water intended for drinking is measured against physical, chemical, radiological and microbiological standards outlined in the federal Guidelines for Canadian Drinking Water Quality. To that end, your water is tested regularly for viruses, bacteria (e.g. e-coli), parasites (e.g. giardia and cryptosporidium), and turbidity. The guidelines recommend that water intended for drinking have a turbidity level < 1 NTU.
Peachland Water Quality staff collects samples daily to confirm the online turbidity data.
How will elevated levels of Turbidity be reported?
In keeping with the Guidelines for Canadian Drinking Water Quality and B.C.'s Drinking Water Protection Act, water suppliers will notify customers of turbidity levels that exceed 1 NTU. A Turbidity Index on the supplier's website will indicate if the water is 'Good' (<1 NTU), 'Fair' (1-5 NTU), or 'Poor' (>5 NTU), and provide recommendations for each. 'Fair' and 'Poor' ratings will also be publicized through the media.
Why is turbidity an important water quality indicator?
Bacteria, viruses and parasites such as giardia and cryptosporidium can attach themselves to the suspended particles in turbid water. These particles then interfere with disinfection by shielding contaminants from the disinfectant (e.g. chlorine). Chlorine is not effective in deactivating cryptosporidium.
For more information regarding health issues related to turbidity contact the Interior Health Authority at: (250) 862-4200 or visit www.interiorhealth.ca.
If boiling water is impractical, you should seek an alternative potable water supply such as bottled water