Regulatory Impact Assessment (RIA)
Part G (Hygiene) of the Building Regulations
Proposed requirement for Dual Flush Toilets
November 2006
Section 1: Context
1.1 Policy Context
Despite the plentiful rain we experience in this country, fresh water is not an infinite resource. On a global scale, usable fresh water accounts for only 3 % of total water resources, the other 97% of the world’s water is saline or seawater and therefore not suitable for drinking.
As Ireland’s population increases so does its demand for water. This results in increased amounts of water being extracted from our rivers. This can have a negative effect on the local ecology.
Once the water is extracted, it requires treatment in order to make it suitable for consumption. Treatment generates demand fir the production and distribution and storage of certain chemicals e.g. chlorine. The treatment process costs approximately €1.00/m3[1].
Energy is needed to treat the water, to deliver it to the end user and then re-treat it as sewage. This energy usage adds to the volumes of CO2 emitted in Ireland and this, in turn, contributes to the global problem of climate change. Ireland may as a result of climate change experience higher rainfall in winter and associated flooding along with lower summer rainfall resulting in water shortages. This may make it more difficult to meet the increased demand for drinking water.
[2]According to the European Environment Agency, the average consumption for all households’ purposes in the EEA is about 150 litres per capita (1999)[3]. On this basis the average water consumption per person in Ireland comes to a staggering 55,000 litres per person per year. The third biggest user of water is the WC, accounting for almost 35% of a person's average daily water consumption.[4]
1.2 Regulatory Context
Part G (Hygiene) of the Building Regulations 1997 sets out the legal requirements for sanitary installations. At present, it requires that adequate sanitary conveniences be provided in a building. Technical Guidance Document (TGD) G advises on the scale of provision, the siting of appliances and their design and installation. TGD G refers to the Irish Standard
(I.S.) 70:1980: “Water Closet Cisterns for Domestic Use”. This standard covers WC flushing cisterns with discharges of 9 (+or -0.5) litres, or in the case of a dual flush[5], a short flush of 4.5 (+1 or –0) litres.
Under the Local Government Act 1994 (No.8 of 1994), Dublin City Council published a revised set of byelaws in 2003. These limited the maximum flush volume to 6 litres for both new and replacement WCs in buildings. This has influenced the marketplace in so far as many WCs sold today are 6 litres. However, these bye-laws only apply in Dublin City whereas the Building Regulations apply nationally.
The draft Part G Regulations and related TGD G propose a maximum flush volume of 6 litres and a reduced flush volume no greater than two thirds of the maximum (maximum 4 litres) in all new buildings and when WC are being replaced in existing buildings.
Dual flush toilets are being voluntarily installed as the norm on most modern commercial buildings demonstrating the water saving advantages of dual flush are accepted in the market place.
Mr Dick Roche, TD, Minister of the Environment, Heritage and Local Government announced, during an Oireachtas debate on the Water Services Bill, that he intended to make dual flush toilets mandatory under the Building Regulations.
1.3 Statement of objectives
General objectives:
- Conservation of Water- a precious natural resource
- Optimisation of Capacity- of existing piped water supply systems, and thereby defer need to invest in the augmentation of existing supplies.
- Conservation of Energy - energy is the greatest cost in producing drinking water
- Reduced demand for Chemicals- required for the treatment of potable water e.g. Chlorine
- Cost Savings - to local water services authorities and commercial water users
Immediate objective:
- Ensure that all WCs in new buildings and replacement WCs in existing buildings are dual flush, in order to reduce the volume of water used.
Section 2: Cost Benefit Analysis
2.1 Assumptions
The cost benefit analysis below is based on the assumption that users understand and know how to use dual flush toilets correctly.
Dual flushes are flushing cisterns with two modes of operation, one delivering a larger volume than the other. The full flush is designed to remove solids and paper and the reduced flush to remove urine.
They act as water saving mechanisms as only one out of five visits to the WC warrants a full flush. [6] It is estimated that 5 flushes are made per person per day.[7]
The analysis is based on new domestic buildings only, as many commercial premises are already using them.
The cost of water treatment is estimated at €1.00/m3. This is the average cost for abstracting, treating and distributing drinking water to consumers; it also includes treatment and disposal of treatment by-products. It excludes the cost savings that arise from the reductions in wastewater volumes that require treatment. The figure does not take into account the capital costs of building the facility or the administrative costs associated with operating it, which would arise in any case.
The economic value of the reduction in the demand on our national water resources- rivers, lakes and underground sources- cannot be estimated but is one of the biggest benefits of dual flush toilets
2.2 Analysis
Per WC
A survey of 15 suppliers in the greater Dublin area was carried out. The results are presented in Table 1 below.
In general the prices for bathroom suites vary considerably from basic to high end. This survey focused on the low to middle range.
Findings:
- The price of a basic dual flush toilet is on average 0% to 30% (approx) more expensive than an equivalent single flush toilet.
- Dual flush toilets are available in most ranges.
- Within a range that has both dual flush toilets and single flush, often both are the same price.
It is clear from the findings that some manufacturers are charging a premium and others not for dual flush toilets. Should they become standard practice for new and replacement installations, market forces are likely to create a situation where there is little or no difference in price.
Nationally
Table 2 below shows the daily usage of water for flushing per household using single and dual flush toilets.
The single flush figures are based on 9litre, 7.5litre and 6litre cisterns. This is due to the fact that some existing houses will have these bigger volumes. Others will have been renovated to incorporate lower volume flushes and most new houses (since 2003 at least) will have 6 litre cisterns.
The dual flush figures are based on the most common 6/4litre model used in the ratio of 4 low flushes (4litres) to 1 full flush (6 litres).
Table 3 highlights the water savings between single flush of 9, 7.5 and 6 litre and the 6/4 dual flush. The reductions are 51%,41% and 27% respectively.
This translates into between 2 billion and 700 million litres of water savings per annum.
Reductions in water usage such as these are valued between €2 million and €700,000.
Realistically, with the prevalence of 6 litre cisterns on the market and the high number of renovations in the domestic market it is likely that savings will be nearer the lower end of these ranges ie 27% savings, 700million litres and €700,000 per annum.
The capital cost of constructing 2 to 4 standalone new treatment plants to provide a total of 700 million litres/year would be in the order of €2.8m to €3.4m ( for 5 to 8 standalone plants to provide 2 billion litres/year would be in the order of €5.8m to €7.5m). If the capacity was to be provided by extending existing plants, the cost would be between 50% to 70% of these ranges.[8]
RIA- Part G (October 2006) - Public Consultation
Manu. / Range / Flush / Supplier 1 / Supplier 2 / Supplier 3 / Supplier 4 / Supplier 5 / Supplier 6 / Supplier 7 / Supplier 8 / Average Price / Average % Difference between Single and Dual FlushManu 1 / X / Single / 125 / 105 / 129 / 118 / 105 / 105 / 115
Y 2 / Dual / 150 / 150 / 31% / Increase
Z 1 / Single / 176 / 195 / 176
Z 1 / Dual / 176 / 195 / 200 / 175 / 135 / 176 / 176 / 54% / Increase
Manu 2 / A / Single / 160 / 180 / 130 / 165 / 159
B3 / Dual / 325 / 250 / 208 / 261 / 64% / Increase
C4 / Dual / 170 / 170 / 7% / Increase
Notes:
1. Z is a low - middle range product from Manu 1
2. Y was a little cheaper than Z but it wasn’t widely used - hence little price information
3. B is a middle range product from Manu 2 but yet the most common
4. C is cheaper than B but not widely used - hence little price information
5. Manufacturer 1 & 2 have approximately 50% of the Irish market
Manu. / Range / Flush / Supplier 9 / Supplier 10 / Supplier 11 / Supplier 12 / Supplier 13 / Supplier 14 / Supplier 15 / Average Price or Range / Average % Difference between Single and Dual Flush
Manu 3 / Single / 170 / 160 / 165
Dual / 240 / 160 / 200 / 21% / Increase
Misc / Single / 186 / 199-400 / 77 / 190 / 319-400 / 77-400
Dual / 300 / 199-400 / 356 / 302-400 / 199-400 / 0-150% / Increase
TABLE1: Survey of Dual Vs Single Flush Toilets - June 06
RIA- Part G (October 2006) - Public Consultation
1. Single Flush Toilets:Volume of Flush (litres) / 9 / 7.5 / 6
No of people per household 1 / 3 / 3 / 3
No of flushes per day 2 / 5 / 5 / 5
Daily usage per household using single flush (litres) / 135 / 112.5 / 90
Note 1: Housing Policy, DOEHLG; Note 2: Environment Agency, UK
2. Dual flush Toilets:
Volume of flush in Litres / No. of people per household / Ratio of flushes - Option 1
Volume of High Flush / 6 / 3 / 1
Volume of Low Flush / 4 / 3 / 4
Daily usage per household using dual flush (litres) / 66
TABLE 2: Daily usage of water for flushing per household using single and dual flush toilets
TABLE 3: Water savings
Option 1: Ratio of low to high flush usage 4:19 litres / 7.5 litres / 6 litres
Daily usage per household using single flush / 135 / 112.5 / 90
Daily usage per household using dual flush / 66 / 66 / 66
Daily water savings per household / 69 / 46.5 / 24 / Litres
%Reduction / 51% / 41% / 27%
365 / 365 / 365
80,000 / 80,000 / 80,000 / New houses pa
Annual water savings / 2,014,800,000 / 1,357,800,000 / 700,800,000 / Litres
Treatment Costs / 1.00 / 1.00 / 1.00 / €/m3
Value of annual water savings / €2,014,800 / €1,357,800 / €700,800
RIA- Part G (October 2006) - Public Consultation
[1] This is the average cost for abstracting, treating and distributing drinking water to consumers; it also includes treatment and disposal of treatment by-products. It excludes the cost savings that arise from the reductions in wastewater volumes that require treatment. The figure does not take into account the capital costs of building the facility or the administrative costs associated with operating it, which would arise in any case. Source: Water Services, DOEHLG
[2]
[3]
[4] Water Services Investment Programme, DOEHLG
[5] Dual flushes are flushing cisterns with two modes of operation, one delivering a larger volume than the other. The full flush is designed to remove solids and paper and the reduced flush to remove urine. They act as water saving mechanisms as only one out of five visits to the WC warrants a full flush.
[6] Nick Grant and Mark Moodie; WCs; best practice since the Water Fittings Regulations 1999. Elemental Solutions and also Environment Agency, UK
[7]
[8] Water Services Investment Programme, DOEHLG