Part 1
Overview of Water Quality in England and Wales
For 2001, a further improvement in overall compliance with 99.86% of 2,823,914 tests carried out complying with the Regulations.
Coliforms absent from all samples at 1,253 (90.40%) of the 1,386 water treatment works.
Coliforms absent from at least 95% of samples (the regulatory requirement) at 4,740 (99.87%) of the 4,746 service reservoirs.
Continued improvement in compliance in water supply zones with 99.83% of the 2,004,739 tests carried out in zones complying fully with the numerical standards.
Notable improvement in compliance with standards for iron, THM, and lead.
Summary Information
Number of water companies*: 26 Number of consumers supplied: 52.7 million Amount of water supplied: 15,641 Ml/d Proportion from surface water sources: 68% Proportion from groundwater sources: 32% Number of treatment works: 1,386 Number of service reservoirs: 4,746 Number of water supply zones: 2,305 Total length of mains: 325,988 km
* Including inset appointments Introduction
Overview Format
This part of the report provides a summary of the overall quality of drinking water supplied during 2001 to over 52 million consumers in England and Wales, by the 26 water companies.
The Overview Chapter is split into five general sections as follows:
- Overall Water Quality in 2001 – gives summary statistics on water supply information in England and Wales, levels of overall compliance with regulatory standards, and a brief comparison with previous years.
- Microbiological Quality of Water Leaving Treatment Works – expands on the information in the Overall Water Quality section and provides further data and analysis on the compliance with standards for water leaving water treatment works in 2001, compared with previous years.
- Microbiological Quality of Water in Service Reservoirs – expands on the information in the Overall Water Quality section and provides additional data and analysis on the compliance with standards that apply to water in service reservoirs, compared with previous years.
- Water Quality in Water Supply Zones – provides greater detail on compliance with the standards for microbiological parameters and for 55 parameters with numerical standards that apply to water supply zones.
- Comparisons of Drinking Water Quality between Companies – gives a statistical comparison, using the Overall Quality Index and the Operational Performance Index, of compliance data
Statistical Significance
Throughout this report, and particularly in this Section, the term ‘statistically significant’ is commonly used where comparisons are made between data from different years. Often, apparent differences in the proportion of samples breaching the standards are affected by factors other than water quality, such as differences in the overall number of tests carried out, or changes to the total number of treatment works, service reservoirs or zones. Also, as the number of tests carried out is often very large, and the number of breaches of the standards comparatively small, in many cases the differences are sufficiently small to be attributable to random variations.
Therefore, in each case ‘significance’ has been tested using accepted statistical techniques (normal approximation to the binomial distribution; 95% confidence interval) to determine those cases where statistically significant differences can be said to have occurred.
Where changes have been found to be ‘not statistically significantly different’ it indicates that, whilst the numbers may be different, no strong conclusions can be drawn concerning trends.
Presentation of Data
For each of the sections dealing with treatment works, service reservoirs and water supply zones, data for 2001 is presented in table form. Comparative data from 2000 and 1999 has also been included.
Where information concerning overall compliance or numbers of non-compliant samples is shown, histograms have been used to represent the data for each year. In cases of individual parameters, line charts have been used as they are considered to be the most effective form to show the trends in compliance with standards over the last ten years. The contributions of individual parameters to the overall level of non-compliance, in water supply zones, in 2001 is shown in the form of a pie chart.
Overall Water Quality in 2001
At water treatment works, in service reservoirs and in water supply zones, the companies carried out a total of 2,823,914 tests in 2001. Of these, 99.86% demonstrated compliance with the relevant water quality standards. This compares with 99.83% for 2000 with the number of samples breaching the standard reducing from 4,475 in 2000 to 4,054 in 2001.
The overall number of tests failing the standards has decreased from 50,476 in 1992 to 4,054 in 2001. This represents a reduction of 92% over the last ten years.
There has been a substantial increase in the total number of samples taken in 2001 over the number taken in 2000 (2,684,295). This has been due to a few companies reporting a significantly greater number of results for individual pesticides as a result of modifications to the use of or introducing authorised supply points for pesticide sampling.
Water companies may apply to the Inspectorate to take samples for certain selected parameters from supply points rather than from consumers’ taps. Supply points can only be used for parameters that are unlikely to change in concentration as the water passes through the distribution system.
Authorised supply points usually relate to a treatment works or service reservoir. The results of samples taken at supply points are then applied to those water supply zones for which the supply point is the sole source of water.
Whilst a further reduction in the number of breaches of the standards has occurred in 2001, the increase in the number of tests carried out has had an impact on the overall percentage compliance figures.
Coliforms were absent from samples taken from 1,253 (90.40%) of the 1,386 sampling points at water treatment works.
Total coliforms were absent from at least 95% of samples (the Regulatory standard) taken from 4,740 (99.87%) of the 4,746 sampling points at service reservoirs.
Figure 1 below shows the overall compliance with the standards, specified in the Water Quality (Water Supply) Regulations 1989, over the last ten years. The improvement is best seen in Figure 2, which shows the decreasing number of breaches of the standards.
The improvement since 1992 is mainly due to significant reductions in the number of breaches of the total coliform and faecal coliform standards at water treatment works and in service reservoirs, and of the iron, lead and THM standards in zones. There have also been lesser, but notable, contributions from reductions in breaches of the standards for a number of other parameters such as aluminium and pH.
Figure 1
Figure 2
Microbiological Quality of Water Leaving Treatment Works
Figure 3 below shows the companies’ performance in 2001, with data for 2000 and 1999 for comparison.
Figure 3 Microbiological Quality of Water Leaving Treatment Works
2001 2000 1999 Number of water treatment works COLIFORMS Total number of tests 164,429 173,544 183,773 – number containing coliforms 169 247 215 – % containing coliforms 0.1 0.14 0.12 Treatment works with coliforms detected 133 182 165 – % of all works 9.6 13.11 11.4 FAECAL COLIFORMS Total number of tests 164,462 173,553 183,804 – number containing faecal coliforms 30 43 36 – % containing faecal coliforms 0.02 0.02 0.02 Treatment works with faecal coliforms detected 28 41 32 – % of all works 2.02 2.95 2.21
Figures 4 and 5 below show the companies’ performance in meeting the regulatory requirements at water treatment works over the last ten years.
In Figure 4, overall compliance with the regulatory requirements since 1992 is shown. Figure 5 shows the trend in the proportion of treatment works at which coliforms or faecal coliforms have been detected over the last ten years.
Figure 4
Figure 5
There has been a decrease, since 2000, in the number of treatment works, and samples from treatment works, where both total and faecal coliforms were detected.
A total of 169 samples taken from 133 treatment works (9.60% of all works) were found to contain total coliforms, compared with 247 samples from 182 treatment works (13.11%) in 2000. Faecal coliforms were detected in 30 samples taken from 28 treatment works (2.02% of all works), compared to 43 samples from 41 treatment works (2.95%) in 2000.
The decrease generally follows the overall ten-year trend, which has seen continued improvement in water quality leaving treatment works. At 99.94%, the overall compliance at treatment works is higher than in any other year.
Examination of all 26 companies’ individual performance at treatment works compared with last year showed that, for 23 of the companies, there was no statistically significant difference from 2000. Three companies had shown a statistically significant improvement but none showed a significant deterioration.
The detection of total coliforms and faecal coliforms in treated water does not mean that the water is harmful to health. They are indicator organisms, not harmful themselves, which give a warning that more dangerous organisms may be present. They are easy to detect and their presence in water leaving a treatment works can indicate that the effectiveness of the treatment or disinfection processes has been reduced.
During 2001, on every occasion total coliforms and faecal coliforms were found, the water companies concerned carried out investigations to determine the nature of the problem. In the vast majority of occasions, the Inspectorate considered the breaches of the standard to be either trivial, or unlikely to recur as a result of remedial actions taken by the companies. However, the Inspectorate has considered, or has taken, enforcement action against three companies in respect of breaches of the total coliform standard at six treatment works. This action will require the companies concerned to take the necessary measures to prevent further breaches.
Microbiological Quality of Water in Service Reservoirs
Figure 6 below shows the companies’ performance in 2001, with data for 2000 and 1999 for comparison.
Figure 6 Microbiological Quality of Water in Service Reservoirs
2001 2000 1999 Number of service reservoirs 4,746 4,782 4,830 COLIFORMS Total number of tests 245,126 246,133 248,615 – number containing coliforms 445 507 525 – % containing coliforms 0.18 0.21 0.21 Service reservoirs with coliforms detected 400 427 448 Service reservoirs with coliforms detected in more than 5% of samples 6 18 22 – % of all reservoirs 0.13 0.4 0.46 FAECAL COLIFORMS Total number of tests 245,158 246,174 248,646 – number containing faecal coliforms 62 81 95 – % containing faecal coliforms 0.03 0.03 0.04 Service reservoirs with faecal coliforms detected 58 72 90 – % of all service reservoirs 1.22 1.51 1.86
Figures 7 and 8 below show the companies’ performance in meeting the regulatory requirements at service reservoirs over the last ten years.
In Figure 7, overall compliance with the numerical standards for coliforms and faecal coliforms since 1992 is shown. Figure 8 shows the trend in the proportion of service reservoirs breaching the standards for coliforms or faecal coliforms over the last ten years.
It should be noted that, whilst Figure 8 shows the proportion of service reservoirs where coliforms were absent from at least 95% of samples taken over the year (the regulatory standard), all incidences of detections of coliforms have been used in generating Figure 7.
Figure 7
Figure 8
In 2001, the number of service reservoirs, and samples from service reservoirs, containing total coliforms and faecal coliforms fell again. In all cases the numbers are lower now than at any time in the last ten years.
Only 6 (0.13%) of the 4,746 service reservoirs in England and Wales failed to comply fully with the standard for total coliforms, and only 58 (1.20%) failed to comply fully with the standard for faecal coliforms. This represents a reduction of 94% in the number of service reservoirs failing to comply with the standard for total coliforms, and 84% reduction in the number failing for faecal coliforms, since 1992.
During 2001, a total of 490,284 microbiological tests were carried out on samples taken from service reservoirs. Total coliforms or faecal coliforms were detected on 507 occasions, giving an overall compliance figure of 99.90%.
On each occasion that the standard for total coliforms or faecal coliforms were breached, the companies carried out an investigation into the cause and, where necessary, took appropriate remedial action. In the majority of cases, the Inspectorate considered the breaches to be either trivial, or unlikely to recur because of the actions taken. However, enforcement action has been taken, or is under consideration, for breaches of the faecal coliform standard at one service reservoir.
Water Quality in Water Supply Zones
Figure 9 below shows the companies’ performance in 2001, with data for 2000 and 1999 for comparison.
Figure 9 Water Quality in Water Supply Zones
Parameter Tests in 2001 Zones in 2001*: 2,306 Tests Taken Contravening PCV Non-compliant Number % 2001 2000 1999 Coliforms 149,688 761 0.51 5 8 4 Faecal coliforms 149,702 61 0.04 60 60 61 Colour 41,412 3 <0.01 2 8 3 Turbidity 64,992 44 0.07 42 33 75 Odour 15,059 6 0.04 5 6 11 Taste 14,994 2 0.01 2 5 6 Hydrogen ion 64,592 12 0.02 8 27 25 Nitrate 34,695 132 0.38 26 10 10 Nitrite 31,797 1,032 3.25 149 184 203 Aluminium 37,344 29 0.08 27 35 41 Iron 52,092 513 0.99 345 375 440 Manganese 39,856 111 0.28 94 97 113 Lead 19,444 123 0.63 105 135 212 PAH 11,048 285 2.58 168 174 264 Trihalomethanes 11,337 84 0.74 35 45 27 Total pesticides 33,691 4 0.01 4 1 4 Individual pesticides 751,957 78 0.01 70 44 81 All others 481,039 68 0.01 49 28 26 TOTAL 2,004,739 3,348 0.17 – – – * 2,316 in 2000; 2,324 in 1999
Figure 10 below shows the overall compliance with water quality standards in companies’ water supply zones over the last ten years.
The ‘compliance figures’ in this chart have been derived by taking the total number of tests in zones and the number of occasions on which one or more sample has breached the relevant numerical standard (‘point breaches’). This does not take into account parameters such as total coliforms where compliance is based on 5% of samples, or certain other parameters where compliance with the standard is based on an average of results. The data is, however, considered a useful indicator of the trend in water quality in supply zones over the last ten years.
Figure 10
Since 1992, there has been a reduction in the number of test results from zones which failed to comply with the relevant standards. In 2001, only 3,348 (0.17%) of the 2,004,739 tests carried out in zones failed to comply fully with the standards, compared with 47,639 (1.72%) of 2,775,586 samples failing in 1992.
Trends over the last ten years in compliance with the standards for the 55 individual parameters which have a numerical standard, and which companies must test for in all of their water quality zones, are represented in the following six charts (Figures 11 to 16). In this case the percentage figures are calculated from data for zonal compliance and therefore do take account of cases where compliance is based on a percentage, or on average results.
For clarity, the parameters have been arranged in groups of broadly similar character, and the charts below generated according to these groups, but it should be stressed that these groupings do not have any scientific or regulatory significance. The groups are categorised as follows.
- Microbiological Parameters: namely total and faecal coliforms;
- ‘Aesthetic’ Parameters: parameters which, in general terms, affect the appearance, taste or odour of the water;
- ‘Metals’ Parameters: trace metals, such as iron or lead, which may be detected in drinking water;
- ‘Organic’ Parameters: parameters such as pesticides, and disinfection by-products which companies regularly monitor for;
- ‘Ionic’ Parameters: pH, nitrate and nitrite;
- All Other Parameters: a combined figure for the remaining 38 parameters, regularly tested for, but rarely found at non-compliant levels.
For further information on a specific parameter, please refer to the Quality Standards Table in the introduction to Part 2 of this report.
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Non-Compliant Zones
A zone may be non-compliant because a single result has breached a standard. Some of these breaches have been regarded as trivial in the compliance assessment and do not indicate a serious problem with water quality.
In other cases, a breach of a standard, although not trivial, is considered unlikely to recur as a result of remedial action taken by the company, or is being remedied through an undertaking given by the company to carry out appropriate work as part of an improvement programme.
Enforcement action has been considered in a small number of cases, where the contravention is likely to recur and where no remedial action is in place. Such action has been considered, or is under consideration, for breaches of standards for ten parameters in 28 (1.22%) water supply zones. Full details of this enforcement action are given in Part 3, Section E, of this report and in individual company sections.
Figure 17 below shows those parameters for which breaches of standards have occurred in 2001. Each is shown as a percentage of the 3,348 individual breaches in water supply zones. A commentary on significant parameters is given below.
Figure 17
Microbiological Parameters
The number of zones breaching the total coliform standard has shown a slight decrease since last year. The decrease is not statistically significant but it is lower than in any year except 1999. The number of zones breaching the faecal coliform standard is the same as last year.
Breaches of the standards in samples taken from consumers’ taps can sometimes be caused by the condition of the plumbing and therefore do not necessarily reflect fully the microbiological quality of the water supplied. However, companies are expected to take appropriate action in the event of any breach of the microbiological standards. The Inspectorate requires evidence, including repeat sampling and sampling from related points, before accepting that the condition of a consumer’s tap may be responsible for the breach.
A small number of zones breaching the microbiological standards are already covered by undertakings. For the remainder, the Inspectorate is ensuring that appropriate steps are taken by the companies to restore compliance with the standard.
Iron
There has been a decrease in the number of water supply zones failing to comply with the iron standard during 2001. A total of 345 (14.97%) zones failed to comply with the iron standard in 2001 compared to 375 (16.19%) zones in 2000.
Iron can affect the taste and appearance of the water, and give cause for concern. However, there are no health risks associated with the breaches of the iron standard. Many of the breaches are the result of localised problems within the distribution system, especially where there are unlined cast iron mains. In a few cases the breaches are due to inadequate removal of iron at a treatment works.
Nearly all the breaches occurred in zones covered by undertakings. These undertakings have been given by the companies to carry out improvements in the distribution system or at treatment works. The steady underlying trend of improving compliance with the iron standard can be attributed to the work being carried out under these undertakings. These improvements should continue as the programmes of work are progressed.
Lead
There has been a steady decrease every year since 1992 in the number of zones not complying with the lead standard. A total of 105 (4.56%) zones failed to comply with the standard for lead in 2001 compared to 1992, when 549 (21.13%) zones failed to comply.
This continued improvement largely reflects the additional treatment that companies have installed, or are installing, under the terms of their undertakings in respect of lead. Such treatment makes the water less able to dissolve lead from pipework, i.e. it makes it less plumbosolvent.
The main sources of lead in drinking water are lead service pipes, i.e. the connection from the water main to the property, or internal lead plumbing, which may be present in older buildings. Occasionally, the use of lead solder can cause problems. When considering breaches of the lead standard, it is particularly important to bear in mind that the nature and condition of the pipework at the sampling location may greatly influence the outcome. The detection of lead in samples taken from a particular zone does not necessarily mean that the water is plumbosolvent or that samples from other properties in the zone will fail the standard. As long as lead continues to be present in household plumbing it is likely that occasional breaches of the lead standard will occur in water at consumers’ taps.
- The current standard for lead is 50 µg/l. The new Drinking Water Directive sets a more stringent interim standard for lead of 25 µg/l, to be achieved by the end of 2003, and a final standard of 10 µg/l, to be met by the end of 2013. These changes to the standard have been incorporated into the new Water Supply (Water Quality) Regulations 20001. Companies have strategies and legally binding programmes of work for achieving compliance with these tighter standards.
1 The Water Supply (Water Quality) Regulations 2001 in Wales
Nitrite
The number of zones contravening the standard for nitrite has shown a slight decrease since last year. The decrease is not statistically significant but has resulted in the lowest level of non-compliance to date. However, with 1,031 individual tests found to contain nitrite above the standard, it was the most commonly failing parameter.
Detection of nitrite above the current standard of 0.1 mg/l is usually associated with the use of chloramines as a disinfectant. Chloramines are formed by the reaction of chlorine and ammonia, which is introduced into the water supply as an alternative disinfectant to chlorine. This method of disinfection has the benefit of reducing consumer complaints of chlorine taste or odour. Over time, and under certain conditions, chloramines can break down and one of the by-products formed is nitrite.
Where chloramination is used, companies are working to optimise the process to minimise the risk of nitrite production. Since 1991, the number of zones not complying with the standard has decreased from 317 (12.3%) to 184 (7.9%). Like all parameters, there is a wide margin of safety between the standard and the concentration which is considered potentially harmful.
The new EC Drinking Water Directive contains a revised combined standard for nitrite and nitrate, which is based on a formula and recognises the relationship between the two parameters. The Directive also introduces a separate individual nitrite standard which applies at the treatment works, rather than in water supply zones, to take account of the use of chloramines. These changes have been taken into account when making the new Water Supply (Water Quality) Regulations 2000, which implement the Directive.
Polycyclic Aromatic Hydrocarbons (PAH)
A steady rise in the number of zones not complying with the standard for PAH was apparent from 1991 to 1996. This trend was reversed in 1997 and a downward trend occurred until 2000. This reflected the programmes of work being carried out as part of the companies’ distribution system undertaking. However, in 2001, the number of zones not complying increased to 168 (7.3%) from 147 (6.4%) in 2000. This slight increase is not statistically significant.
PAH is derived from the distribution system and is often a localised problem. Breaches of the standard in a zone does not mean that the entire water supply in that zone is non-compliant. The short term remedial measures taken by water companies to alleviate acute water quality problems, such as discolouration, may give rise to breaches of the PAH standard. The distribution undertakings require companies to take account of non-trivial breaches of the PAH standard when assessing priorities for mains renovation.
Although all PAH breaches are investigated, detailed examination of the results shows that, in almost all cases, the contravention of the standard has been caused by only one of the six indicator substances determined in the definition of PAH, namely fluoranthene.
The new EC Drinking Water Directive no longer includes fluoranthene as an indicator substance in the PAH standard and this has been taken into account during the making of the new Regulations to implement the Directive. Water distribution undertakings have been adjusted accordingly to give priority to breaches of other standards.
Pesticides (Individual and Total)
During 2001, eleven individual pesticides were detected above 0.1µg/l in 59,044 samples. In every instance the concentrations found corresponded to exposures far smaller than those known to be harmful or likely to affect health.
There has been a significant increase in the number of zones breaching the individual pesticide standard. In 2001, 70 (3.04%) breached the standard compared with 44 (1.90%) in 2000. The increase in numbers has been due in part to a number of companies making increasing use of authorised supply points for individual pesticides in 2001. Because of the way in which the results of samples taken from supply points are applied to water supply zones, a failure of the individual pesticide standard in a single sample at a supply point, results in an increase in the number of zones failing to meet the individual pesticides standard. There was also an increase in zones failing to meet the total pesticide standard, but this was not considered statistically significant. Enforcement action has been taken in those cases where breaches are likely to recur.
Between 1992 and 2000, there had been a very significant reduction in the number of zones breaching the standards for both total and individual pesticides. These reductions reflect the completion and commissioning of most of the improvement programmes in which companies are engaged to deal with pesticides. Although there was an increase in the number of zones failing to meet the standard for individual pesticides in 2001, compliance remains significantly higher than in 1992.
Turbidity
- There has been a slight increase in the number of zones failing to meet the turbidity standard compared with last year. In 2001, 42 (1.82%) zones breached the standard compared with 33 (1.4%) in 2000. However, this is not statistically significant.
Manganese
The number of zones failing to meet the manganese standard has remained the same as in 2000. The majority of the breaches occurred in zones covered by undertakings.
Other parameters
- In 2001, all zones complied with the Regulations in respect of 23 of the other 38 parameters with numerical standards. The standards for a further 15 parameters were breached on only a few occasions in a small number of zones.
Summary Information
Figure 18 below provides a summary of the key information for each of the 26 water companies, listed alphabetically.
It is not designed to make any direct comparisons between companies. The issue of comparison is covered in the next section.
Figure 18
Company Name Consumers Supplied Water Supplied (Ml/d) ProportionSurface Water Proportion Ground Water Number of Treatment Works Number of Service Reservoirs Number of Zones Length of Mains (Km) Samples taken at Treatment Works Failures for Total Coliforms Failures for Faecal Coliforms Samples taken at Service Reservoirs Failures for Total Coliforms Failures for Faecal Coliforms Total Samples Taken in Zones Failures in Zones Total Tests Taken Total Number of Failures % Compliance Albion 300 0.083 100% 0% 0 0 1 0 0 0 0 0 0 0 490 1 490 1 99.80% Anglian 4,100,000 1,200 48% 52% 146 385 189 35,995 28,354 3 0 41,072 27 2 136,090 718 205,516 750 99.64% Bournemouth & West Hants. 432,000 157 82% 18% 9 23 15 2,800 4,696 1 0 2,278 3 0 9,415 31 16,389 35 99.79% Bristol 1,086,000 290 75% 25% 16 184 52 6,500 6,030 1 0 18,750 7 1 18,504 30 43,284 39 99.91% Cambridge 291,700 72 0% 100% 22 33 14 2,194 2,896 0 0 3,574 1 0 4,823 23 11,293 24 99.79% Cholderton 2,100 0.6 0% 100% 1 1 1 44 104 0 0 104 1 1 304 0 512 2 99.61% Dee Valley 257,100 73 96% 4% 7 30 18 1,953 2,704 0 0 3,138 2 1 7,191 12 13,033 15 99.88% Dwr Cymru 2,800,000 1,000 94% 6% 104 558 177 24,900 22,228 5 0 56,878 38 7 81,767 340 160,873 390 99.76% Essex & Suffolk 1,700,000 484 95% 5% 25 104 66 8,370 8,266 5 1 10,356 20 0 98,928 38 117,550 64 99.95% Folkestone & Dover 162,000 50 15% 85% 16 13 10 1,068 2,744 1 0 1,352 0 0 3,305 3 7,401 4 99.95% Hartlepool 91,000 35 0% 100% 3 6 4 513 728 0 0 624 1 0 1,250 2 2,602 3 99.88% Mid Kent 571,800 162 12% 88% 32 66 21 4,167 5,849 4 0 6,578 10 1 15,056 29 27,483 44 99.84% Northumbrian 2,600,000 760 95% 5% 36 245 112 16,687 13,796 2 1 25,386 26 4 167,772 150 206,954 183 99.91% Portsmouth 647,000 186.3 13% 87% 20 43 23 3,200 6,091 9 1 4,334 8 1 12,326 6 22,751 25 99.89% Severn Trent 7,360,000 2,000 65% 35% 179 623 285 41,000 29,102 9 1 62,648 45 3 182,157 198 273,907 256 99.90% South East 1,400,000 370 28% 72% 63 170 90 9,078 11,246 20 5 17,622 36 5 32,641 108 61,509 174 99.72% South Staffordshire 1,200,000 337 50% 50% 22 37 40 5,788 5,662 4 2 3,860 4 0 27,796 23 37,318 33 99.91% South West 1,500,000 445 90% 10% 35 339 81 15,000 16,438 10 0 36,412 44 5 116,213 144 169,063 203 99.88% Southern 2,220,000 578 30% 70% 97 211 116 13,327 15,485 2 0 21,849 4 0 40,218 77 77,552 83 99.89% Sutton & East Surrey 634,000 156 15% 85% 8 33 22 3,374 4,378 1 0 3,526 0 0 16,519 53 24,423 54 99.78% Tendring Hundred 145,000 30 20% 80% 3 8 4 930 746 0 0 896 0 0 2,644 2 4,286 2 99.95% Thames 7,900,000 2,750 75% 25% 101 372 244 31,600 32,092 18 1 38,364 37 2 414,180 380 484,636 438 99.91% Three Valleys 2,900,000 876 42% 58% 83 137 110 13,500 19,583 6 2 14,081 8 2 59,776 119 93,440 137 99.85% Wessex 1,200,000 385 20% 80% 90 320 101 10,800 21,058 8 1 33,807 33 7 99,954 123 154,819 172 99.89% Yorkshire 4,710,000 1,304 78% 22% 109 418 205 31,000 20,672 4 3 42,449 39 8 201,903 174
