The Health (Drinking Water ) Amendment Act 2007

Grading and Backflow

Answers for Water Suppliers

Diana Staveley AWT

Water Supply Size

Large Supplies >10,000 people 1 July 2009

Medium supplies 5,001-10,000 people 1 July 2010

Minor supplies 501-5,000 people 1 July 2011

Small supplies 101-500 people 1 July 2012

Neighbourhood supplies 25-100 people 1 July 2013

The Health (Drinking Water ) Amendment Act 2007

Sections 69S – 69ZC•Adequate Supply •Protect Source •Wholesome Supply•Drinking Water Standards•PHRMP

•Backflow 69ZZZ

Clause 69ZZZ Backflow Prevention

1 July 2008

62 working days ago

69ZZZ Protecting water supplies from risk of backflow

(1) Applies if considers a risk to networked system from contamination.

(2) A network supplier may,-

(a)(i) install backflow prevention on the network side of point of supply.

(b)(i) property owner to reimburse supplier for installation, testing and maintenance.

69ZZZ Protecting water supplies from risk of backflow

or

(2) A network supplier may,-

(b)(ii) allow the owner to install a backflow prevention system with a verifiable monitoring system.

Does this mean BWoF?

(b)(ii) property owner to repair or modify if not functioning adequately.

69ZZZ Protecting water supplies from risk of backflow

(3) Backflows installer must take all reasonable steps not to compromise automatic sprinkler systems.

69ZZZ Protecting water supplies from risk backflow

(4) A network supplier-

(a) must test devices in its network annually at least.

(b) must advise the TA of results

(c) may require occupier to pay reasonable costs for testing.

Backflow Legislation

•Backflow prevention is required at the point of supply between the water supplier and its customer. Health (Drinking Water) Amendment Act

•Also internally in the building to protect the occupants. Building Act

Backflow Plan

1.Policy

2.Containment Protection

3.Device Register

4.Alignment with Building Consents

5.Risk Assessment

6.Survey and Upgrades

1.Backflow Policy

•Develop a Policy. NZWWA Code of Practice or Water Bylaw

a)Containment only Standards for connection.

b)Comprehensive combined with source protection. Building Act and a MOU with Building Control.

c)Stepped/Staged Approach Transitional plan

2. Containment Protection

•New Connections.

•Standard Drawings and Installations.

•Minimum protection levels for connection sizes or risk based.

•Ownership

3. Asset Register

•Data base of devices and test reports

•Link to customer data for charging

•Integrated with other databases ie Asset register, BWoF, GIS, tradewaste and health officers etc for change of use

4. Alignment with Building Consents

•Information flow and cross reference•New buildings•Device data from BC/BWoF process•Most existing devices on property files•Test reports may not be sent in•Change of use consents•Survey results

5. Risk Assessment

•PHRMP•Ranking existing sites for upgrade•Multiple criteria: known hazards from other data sources size of connection, type of water use, low pressure or high break area, ownership•Paper survey Water Use form, database checks

PHRMP GuideDistribution System - Backflow

Prevention ref D2.4Event:

WATER PRESSURE IN THE DISTRIBUTION SYSTEM LOWER THAN PRESSURE IN SUPPLIED PREMISES

NO, INADEQUATE, FAULTY, OR INCORRECTLY INSTALLED BACKFLOW PREVENTION DEVICE

Possible hazards: Germs; chemical determinands.

Level of risk: High

How to Prepare and Develop a PHRMP for Drinking Water Suppliers

How to Prepare and Develop a PHRMP for Drinking Water Suppliers

PHRMP GuideDistribution System– Backflow

Prevention ref D2.4Preventative Measures:•Installation of one of the following backflow prevention devices depending on the level of risk to the supply:

non-testable dual check valve Very Low Hazardtestable double check valve Low and Medium Hazardreduced pressure backflow prevention device High Hazardair gap. All

•Annual inspection and testing of backflow prevention devices

•Develop guidelines in conjunction with local authority so that the supply engineer is informed of changes in the use of premises by the part of the authority concerned with the registration of building modifications.

PHRMP GuideDistribution System– Backflow

Prevention ref D2.4

Checking preventive measures Signs that action is needed•Reports by consumers of gross contamination of tapwater.

•Unexplained fluctuations in chemical and microbiological water quality.

•E. coli or coliforms detected in 100 mL water sample.

•Concentrations of targeted chemical determinands are more than 50% of their MAV.

PHRMP GuideDistribution System– Backflow

Prevention ref D2.4

Corrective action •Determine reasons for low system pressure and rectify if possible.

•Identify the premises from which backflow occurred and install appropriate device (see D2.4.2).

•Check on qualifications of staff undertaking connections.

•Repair/replace.

•Protect from future damage.

6. Survey and Upgrades

•Start with TA properties•Pump Stations RPZs with no hose connections upstream•WWTP VB on hoses safety showers on dedicated lines •WTP backflow on clean in place systems and bores•Pools, parks, depots and municipal buildings •Device data known and annual tests up to date•Hydrant Use•Then do private properties

6. Survey and Upgrades

•Ranked list do one at a time•Surveyor to determine risk, upgrade and liaise with customer•Follow up with correspondence•If not done in time frame install and charge customer•Inform Building Control•Do next one

Practical Considerations

•Executive / Political buy in•Resources skills, staff, funding etc•Non-metered & rural connections•Enforcement•Education•Links with Building Control•Other water supply issues•Low or ungraded supplies

Grading and the Act

• No reference to “The Public Health Grading of Community Water Supplies 2003” in the Act

• Must be on the Drinking Water Register where grades are published.

• Water supplier must comply with requests for information from the DWA

• Grading is undertaken at the request of the DWA.

MoH recommended Grades

Community size Source and treatment Distribution

Greater than 10,000 B a

From 5001 to 10,000 B b

5000 or less C c

Public Health Grading of Community Drinking-Water

Supplies 2003

Q15: Indicate whether the legislative requirements relating to backflow are being implemented.

•69ZZZ Protecting water supplies from risk of backflow 1 July 2008

•69Z Duty to prepare and implement public health risk management plan

Q15: Backflow prevention

15 Backflow prevention (ignore this for bulk water mains)

Tick only one box

Legislative requirements met (0)

Legislative requirements not met, but residual disinfectant (4)

Legislative requirements not met, no residual disinfectant (9)

Q15: Backflow PreventionGrading Evidence

•List of back-flow device locations•Back-flow survey reports•Records of testing of back-flow devices

Drinking Water Assessors

What to look for•A policy and/or defined processes•PHRMP•A register of devices and test reports•Surveying and upgrading of existing connections•Upskilling in backflow for staff and contractors•Contingency plans to deal with an event

Water Suppliers

Where to get help

• NZWWA Backflow Code of Practice for Water Suppliers and the backflow special interest group. www.nzwwa.org

• Diana Staveley diana@awtnz.co.nz

Air Gap

Stock Troughs

Marina Survey

Enforcement

Hydrants

Education

Double Check Device

Reduced Pressure Zone Device

Fire lines

Standard ConnectionsTable 2 Backflow Device Risk Assessment Device Selection Guide Hazard Level Meter size mm Ordinary Connection 15 20 -25 40-50 100+ Very Low (Residential use only) dual n/a n/a n/a Extraordinary 15 20 -25 40-50 100+ Domestic fire sprinkler n/a dual dual n/a Low (Taste and Odour) dual DC DC DC Medium (Illness) DC DC DC DC High (Death) RPZ RPZ RPZ RPZ Unknown use DC DC DC/RPZ* RPZ Fire supply only n/a detector detector detector For examples of hazards see Risk Determination Table 1 of FDC Backflow Policy DC/RPZ* consider size of main/dilution factor and likelihood of backflow Air gap is acceptable for all hazards

Water Supply Bylaw Extract

(10) Backflow prevention

(a)All new connections to the water supply including permit holders will be assessed for cross connections and contamination hazards and the appropriate backflow prevention required, as per the WSA backflow prevention policy.

(b) The WSA may determine which existing customers pose cross connections risks to the water supply. Where, in the opinion of the WSA, there is a contamination hazard to the water supply the WSA or its agents may install the appropriate device on the network side of the point of supply and recover the costs from the customer.

(c) The customer shall ensure that the backflow prevention requirements for within the building, as required by Building Act 2004 and clause G12 Water Supplies of the Building Regulations 1992, are complied with.

Standard Installations Double Check <50mm

Standard Installations100mm+

ABT / IQP / LBP