Policy details

Application Form

1.0. INTRODUCTION

This report was prepared as a consequence of two resolutions of Council relating to utilisation of rainwater in urban areas. The resolutions, as minuted, are reproduced below.

Notice of Motion – Encourage Residents to Install Water Tanks.

Moved. Cr JL McRuvie, Seconded Cr M Carroll.

‘That Council develop a financial incentive program to encourage residents of the Shire to install water tanks on their properties as an aid to the reduction of water use from the reticulated water supply.’

‘That a report be prepared and put to a Works and Infrastructure Committee Meeting.’

Carried

Notice of Motion – Use of Rainwater Retaining Devices.

Moved. Cr MW Prior, Seconded Cr J L McRuvie.

‘That Council actively promote and encourage the proper use of rainwater retaining devices throughout the Shire urban areas, with a view to alleviating problems caused by stormwater run off and to more effectively utilise a finite and precious resource, water.’

Carried

The supply of water to urban areas has evolved remarkably in a relatively short time frame with the current drought highlighting the susceptibility of centralised raw water sources to erratic rainfall patterns.

Water supply quality can be addressed by a diverse range of options, however, ultimately, quantity will limit water use applications that can be guaranteed. Hence, supplementary supplies from rain water tanks have been recognised as a valuable source given the health and amenity issues that initiated the demise of their use in the past can now be addressed.

This report was formulated by reference to a variety of information sources and knowledge to address issues relevant to formulation of the policy. It was envisaged that the policy would be presented for adoption at the first General Meeting of Council for 2003.

2.0. WATER USE AND RAINWATER TANK YIELD.

2.1. Yield

The ability of rainwater tanks to provide an ‘economic’ yield is acknowledged as not being a determining factor with regard to the decision to offer a financial incentive for installation. However, awareness of the estimated percentage of usage that could be satisfied by collecting and using rainwater is valuable. The source of the following information is the Water Wise Technical Information Sheet No. 6. Sheet No. 6 provides the information to enable calculation of the tank size to satisfy a particular demand for various locations in Queensland, or alternatively, the yield for a given tank size at a given location.

An estimate of total daily consumption per person is given as 410 Litres /person/day, with 295 Litres/person/day attributed to outside, toilet and laundry, the usual targets for rainwater use.

For the purpose of calculation, the following parameters were presumed.

Hence, substantial tank sizes would be required to achieve a supply of 200 litres/day with high reliability. The poor yield is due to the sporadic nature of rainfall for this region for ‘normal’ years.

Whilst it is unrealistic to expect installation of tanks of the size noted, the following table provides an indication of the 90% reliability yield for smaller tanks in a 1000mm per annum rainfall zone.

The yield calculations would appear to indicate that a useful yield is not achievable from small tanks and that a minimum size of 4550 litre (1000gallon) should be installed to attract the rebate.

2.2. Installation of Cost

The following example provides an estimate of the purchase and installation cost for a 4550 litre poly tank with two alternatives for uses outside only or inclusion of internal fixtures.

Tank Purchase $700.00

Tank Installation including first flush diversion $250.00

Pressure Pump $350.00

Plumbing Outside only $100.00

Including Internal Fixtures & mains water top-up $750.00

Total Estimated Cost Outside Only $1400.00

Including Internal Fixtures $2050.00

These estimates could be expected to vary by up to 20% due to site variations. Also, it should be noted that only the tank purchase price would increase for a larger tank installation with significantly higher yield achievable.

3.0. TOWN PLANNING IMPLICATIONS AND APPROVAL PROCESSES

3.1. Town Planning

Installation of tanks requires consideration of several Town Planning matters related to maintaining the amenity, hence value, of urban areas.

• It is suggested that non-reflective materials only would be permitted, preferably with colours complimentary to the neighbourhood.

• A total size limit should apply with dimensions limited by tank stands no more than 1000mm high and top of tank restricted to 2700mm above ground level.

• It is anticipated that some residents may prefer to install several small tanks to achieve the minimum capacity eligible for rebate. It is suggested that a limit of 3 tanks would apply with a maximum size limit per tank.

The following scale of sizes is proposed for discussion.

1 Tank – Maximum size 25000 litre

2 Tanks – Combined total 15911 litre

3 Tanks – Combined total 9100 litre

• It is common practice for new developments to include covenants to control a variety of construction aspects for each site. It would be unfortunate if a covenant excluded rainwater tanks, however, property owners could negotiate with the developer.

• Preservation of streetscape should be considered with tank location prohibited from prominent positions at the front of dwellings.

In summary, Town Planning concerns are valid and can be managed by the proposed policy.

3.2 Approval Process

Installation of a tank would require a plumbing application regardless of the proposed use for the water, however, Council’s building department have confirmed that a building permit would only be required if the tank was to be installed on a stand.

4.0 INSTALLATION ISSUES

4.1 First Flush Diversion

A large proportion of the health concerns related to use of rainwater can be alleviated by installation of a system to divert the first runoff from the roof at the commencement of a rainfall event to waste. The first flush has been found to contain the main sources of contamination resulting from air pollution, animal excrement, leaf mulch or small dead animals. Proprietary products are now readily available with prices ranging from $30 - $150 and for various size roof catchments. Installation of a first flush system would be mandatory.

4.2 Screening

The use of screens serves two purposes in relation to rainwater collection systems. Various arrangements are available to exclude leaves and animals from getting or the rain lead. Gutter fitted devices also protect against the risk of fire starting in a gutter filled with leaves.

Screens are also important to exclude small animals or mosquitoes from the tank itself. Properly filled and maintained screens are essential.

4.3 Filters

Installation of filters is usually a consideration where rainwater is the sole household supply. They tend to be expensive, and unnecessary, where water use is primarily for non-potable purposes, hence, inclusion of filters would not be mandatory.

4.4 Integrated Systems with Mains Water Backup

An integrated system with connection to internal fixtures would achieve the highest usage due to constant drain on the tank and hence, greatest available storage volume for any rainfall event. However, this type of system requires a mains top-up facility and backup connections in the event of electricity down time or pump failure. The installation consequence would be the inclusion of appropriate back flow. Prevention devices to avoid cross contamination. The plumbing approval process would address this issue.

5.0 POLICY ISSUES

The preceding sections of this report addressed the practical considerations related to developing a policy to encourage use of rainwater in urban situations. This section proposes the matters requiring Council consideration in formulating the policy core.

5.1 Rebate

5.1.1 Eligibility

The rebate would be available only to the owner of property connected or eligible for connection to the Caves and Capricorn Coast Water Supply Schemes for domestic purposes. Payment of the rebate would be reliant upon making an application in accordance with the policy and payment would be made following final successful inspection of the installation.

Each property would be eligible for rebate once only with a register to be established.

A strategy to generate uptake of the offer would be to initially offer a limited number of rebates, which could be reviewed in the future. A limit of 100 rebates is suggested. For comparison, the Brisbane scheme only offers 1000 rebates. A number of rebates could then be offered for each financial year to facilitate budget certainty.

5.1.2 Amount of Rebate

Determining the amount of rebate to offer for installation of a rainwater utilisation system is difficult. In the first instance, it is appropriate to calculate the value based upon a comparison with headworks charges as a tank system effectively takes on that role.

For the purpose of comparison, a 19kl tank collecting water from 200m² of roof would yield approximately 100 l.p.d with 99% reliability, i.e. the system would be expected to fail for 4 days each year. The cost of this system is estimated as $2,500.00. In comparison, the current headworks charge for 540 l.p.d is approximately $1,250.00 for Yeppoon, ranging to $3,000.00 for Keppel Sands. A midrange of $2,000 would be appropriate. Therefore, the reticulation headworks cost for 100 l.p.d is approximated by ¹⁰⁰/₅₄₀ x 2000 i.e. $370.00.

There are many variables that affect the rainwater system yield, and hence value, including tank size, roof area and type of system. The type of system has the greatest impact due to the consumption difference between a manual, outside use only, versus a integrated system also connected to internal fixtures. The yield varies due to an integrated system ensuring a greater volume of storage available to collect rainwater for each event. The lowest yield situation would result where rainwater is utilised solely for consumption. Hence, it is recommended that 2 levels of rebate should be offered with a higher rebate for an integrated system due to the potentially higher yield, and consequently greater reduction in consumption from the reticulation system. It is evident that larger tanks produce higher yield, however, linking the rebate to tank size would complicate administration unnecessarily.

The rebate levels suggested are:

$250: for a standard alone tank

$500: for an integrated system connected to at least 2 internal fixtures.

5.2 Implementation

The final policy document would include a defined process to gain approval for a system that would be eligible for a rebate. Whilst the current budget has no provision for rebates, the program could be commenced with pro-rata availability for the remainder of this financial year.

5.3 Washing Machines

Laundry water consumption has the greatest potential for reduction by utilisation of alternative equipment readily available. A typical top-load automatic washing machine with a 5kg rating will consume 150 litres for a standard wash. Alternatively, a front load machine would consume 75 litres for the same, or in many cases, better result. Given an average family would wash 7 – 10 loads per week, the potential water saving is 750 litres per week or 39 kilolitres per year. It is suggested that this saving potential is very significant. Unfortunately, the front loading machines are more expensive to purchase and it is suggested that the rebate scheme could be expanded to include a rebate for purchasing a front load machine. This is suggested as a review issue at budget preparation time.

6.0 SUMMARY

Council has expressed an interest in encouraging residents who are connected to the water supply schemes to install rainwater tanks.

This report addresses the issues associated with developing a policy which provides a rebate for installation of systems with tangible benefits, not simply a "feel good" exercise. Minimum and maximum tank sizes have been recommended with two levels of rebate to reflect the greater benefit, and cost, associated with integrated systems.

Subject to discussion with Council, the next step would involve preparation of a policy incorporating the issues addressed by this report.

RECOMMENDATION

That Council resolves to proceed with development of a policy which offers rebates for installation of rainwater utilisation systems with the policy to incorporate the findings of this report.

Dan Toon
MANAGER - COMMERCIAL SERVICES

References

1. Waterwise Technical information sheet No. 6, DPI Qld Water Resources

2. Brisbane City Website, www.brisbane.qld.gov.au

3. Water Sensitive Urban Development – Planning for The Total Water Cycle, Dr Trevor Johnson, Dr Peter Coombs

4. Sustainable Waterfront Rain Harvesting, Environmental Conservation Planning Pty Ltd.

70 Anzac Parade / PO Box 600
Yeppoon,      Qld    4703

 EMail  general@livingstone.qld.gov.au
This web site is best viewed using screen resolution of 800 X 600 and by using Microsoft Internet Explorer 5 and above

Site by