This readme file was generated on 2026-04-07 by Polly Grundy Version history: This is version 2 of this README file Accompanies version 2 of the dataset 'Data relating to Evaluation of the implications and efficacy of proposed changes to haloacetic acid drinking water regulation' Version 2: Updated to include details of published paper to which the dataset pertains and clarity on individual haloacetic acid levels GENERAL INFORMATION Title of Dataset: Data relating to Evaluation of the implications and efficacy of proposed changes to haloacetic acid drinking water regulation Author Name: Polly Grundy ORCID:0000-0003-4899-6954 Institution & Theme: Cranfield University, FEAS Address: Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, UK Email: polly.grundy@cranfield.ac.uk Author/Principal Investigator/Supervisor Information Name: Bruce Jefferson ORCID:0000-0003-4320-628X Institution & Theme: Cranfield University, FEAS Address: Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, UK Email: b.jefferson@cranfield.ac.uk Author/Principal Investigator/Supervisor Information Name: Peter Jarvis ORCID:0000-0003-2740-6740 Institution & Theme: Cranfield University, FEAS Address: Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, UK Email: p.jarvis@cranfield.ac.uk Date of data collection: 2020-01 to 2025-05 Geographic location of data collection: UK drinking water suppliers (location not provided) Information about funding sources that supported the collection of the data: The work was supported by UK Water Industry Research Ltd. (UKWIR) and Engineering and Physical Sciences Research Council (EPSRC) through their funding of the Water Infrastructure and Resilience (WIRe) Centre for Doctoral Training [EP/S023666/1]. SHARING/ACCESS INFORMATION Licenses/restrictions placed on the data: Creative Commons CC-BY Attribution 4.0 International Links to publications that cite or use the data: Grundy, P., Jarvis, P., Fawell, J., Goslan, E., Haley, J., & Jefferson, B. (2026). Evaluation of the implications and efficacy of proposed changes to haloacetic acid drinking water regulation. Science of The Total Environment, 1028, 181741. https://doi.org/10.1016/j.scitotenv.2026.181741 Recommended citation for this dataset: Grundy, Polly; Goslan, Emma; Jarvis, Peter & Jefferson, Bruce. (2026). Evaluation of the implications and efficacy of proposed changes to haloacetic acid drinking water regulation - Data [Data set]. https://doi.org/10.57996/cran-ceres-2807 DATA & FILE OVERVIEW File List: 20260407_HAA9_Survey_v2 File type: .csv Description: A survey was performed to collate the available data on the levels of individual haloacetic acids (HAAs) in treated or not treated UK drinking water sources. This data was obtained from UK water companies who reported the levels obtained and in some cases gave information about the type of water to which the HAA data related. Version 1 created 12/11/2025. Version 2 created 07/04/2026. HAA9 refers to all nine chlorinated and brominated HAAs. The date relates to the date this version of the data was created. METHODOLOGICAL INFORMATION Analytical Procedures: HAAs were reported by the water companies as being analysed by Liquid Chromatography tandem mass spectrometry (LC-MS/MS). Quality assurance: Methods were reported accredited to UKAS standard or internally validated. DATA-SPECIFIC INFORMATION FOR: 20260407_HAA9_Survey_v2 Number of variables: 9 Haloacetic acids 8 Sample Types 6 Sources 5 Treatments 5 Disinfections Number of cases/rows: 31 rows 13 columns Column headings are: Sample Type Source Treatment Disinfection Average of MCAA, µg/L Average of MBAA, µg/L Average of DCAA, µg/L Average of BCAA, µg/L Average of DBAA, µg/L Average of TCAA, µg/L Average of BDCAA, µg/L Average of DBCAA, µg/L Average of TBAA, µg/L Information on data classifications and abbreviations used: Data values were classified in terms of the source water types, treatment type, treatment stage and disinfection process. Where this information was not provided an Unknown category was assigned. Source waters were classified as groundwaters (GW) (fed by boreholes, wells, and springs), surface waters (SW) (from rivers and reservoirs) and mixed waters (MX = GW + SW). Further classification was assigned by catchment type as either upland (UL) or lowland (LL) waters to reflect known difference in the organic make up and background water characteristics. The data provided covered a range of organic removal technologies and was labelled accordingly as either coagulation, ion exchange, nanofiltration (NF) membrane, or minimal treatment. In addition, different disinfection approaches were covered and sub-categorised based on where chlorination was used: Chlorine (Cl Cl – both primary and residual disinfection), Chlorine/chloramine (Cl ClAm – primary disinfection by chlorination – followed by stabilisation to chloramine), UV/chlorine (UV Cl – residual disinfection by chlorination) and Membrane/chlorine (NF Cl – residual disinfection by chlorination). The data also covered several stages within the water treatment process and, to ensure comparability, sub-categories were created to isolate different formation patterns: Raw – untreated source water, prior to treatment or chlorination Raw Formation Potential (FP) – raw water where the potential for formation of DBPs is assessed by adding chlorine in laboratory conditions, generally with a significant excess of chlorine to assess the potential maximum DBP formation Water Treatment Works (WTW) Internal – samples from within the treatment plant, at different stages within the process, which had been exposed to chlorine WTW Miscellaneous – samples where the treatment stage within the WTW is unclear, and includes pilot plants and investigations, and as such is unlikely to be representative Treated Water – combined from WTW final, distribution and tap: WTW Final – samples from the outlet of the plant Distribution – samples from the distribution zone, including storage reservoirs or tanks Tap – samples taken at customer tap INFORMATION FOR ALL DATA FILES: Units: µg/l, micrograms per litre Abbreviations: BCAA, Bromochloroacetic acid; BDCAA, Bromodichloroacetic acid; DBAA, Dibromoacetic acid; DBCAA, Dibromochloroacetic acid; DCAA, Dichloroacetic acid; HAAs, Haloacetic acids; MBAA, Monobromoacetic acid; MCAA, Monochloroacetic acid; TBAA, Tribromoacetic acid; TCAA, Trichloroacetic acid;