Rural Water Scheme Four Day Storage Policy
Published: 16 Mar 2018
Dear Rural Water Scheme Consumer
As you are aware, unexpected interruptions can occur on any water supply. Natural hazards, weather, or other unplanned events such as a damaged pipe can affect the supply and quality of water.
Some of the Waimate District rural water supply intakes draw raw water from local rivers and streams. When the quality of the source water deteriorates due to weather events, and becomes untreatable or disinfection is no longer effective, Council will follow a procedure of “selective abstraction”. This means that the intake pumps will be turned off for a period of time until the source water can be treated and disinfected to a compliant level.
Council’s Rural Water Scheme, Water Supply Policy December 2011 requires all rural consumers to have storage capacity of no less than four times your daily water allocation. It is recommended that you allow four times your peak daily usage on your property, if it is greater than your daily allocation. Therefore in the instance of a supply outage such as “selective abstraction” you will have enough water to see you through for four days.
The diagram shown is what Council recommends your tank set up should reflect.
The tank or tanks should be sized for four days storage minimum. Therefore as an example, 1500 litres per day x 4 days = 6000 litres or greater.
Tanks should be set-up to allow for a minimum reserve storage of one quarter of the capacity, to cover one day’s allocation and keep a household functioning for a day. The portioning of storage needs to be controlled by valves (see diagram). Under normal use, the upper valve (Primary) would be on. The lower valve (Reserve) would normally be off, and only opened when required.
Please note. Follow tank manufacturer’s instructions and warranty, before drilling holes in walls of tanks. An alternative to drilling is a hockey stick shaped riser pipe inside the tank, at a set height/level, which is connected to the manufacturers approved outlet, with a valve on the outside.
To help monitor storage it is recommended to install a “Tell Tale” water level indicator to show you how much stored water is available in the tank. It also gives warning of issues when there maybe water loss through leaks or pipe damage on your property.
When a supply outage occurs that will be greater than 24 hours such as “selective abstraction”, Council have a procedure for relaying the information to its consumers. This is done via social media platforms such as Facebook (www.facebook.com/waimatedistrictcouncil/), the Council’s website (www.waimatedc.govt.nz), plus by informing water scheme committee members, rural schools, churches and Maraes. An advertisement may be published in the local papers. In a more significant event, a notification will go over the radio (Port FM, The Hits), Red Cross Hazard app (www.redcross.org.nz/what-we-do/in-new-zealand/disaster-management/hazard-app/), and a letter drop to consumers.
Paul Roberts, Water and Waste Manager, Waimate District Council.