Remediation Notice relating to groundwater pollution from Contaminated Land at St Leonard’s Court, Sandridge, Hertfordshire

Closed 7 Mar 2019

Opened 7 Jan 2019

Feedback updated 16 Dec 2019

We asked

For a variety of stakeholders including local interest groups, industry and academia to comment on consultation documents relating to a second remediation notice for groundwater pollution from Contaminated Land at St Leonard's Court, Sandridge, Hertfordshire.

You said

  • No objection to the proposals outlined
  • Supported further scavenge pumping and additional monitoring boreholes

We did

Following the consultation, we amended the draft remediation notice. In July 2019 we served a second remediation notice. Both parties appealed and requested the matter be heard at a public inquiry. The Planning Inspectorate, Environment Agency, Crest, and Redland have agreed a period of abeyance to discuss a voluntary scheme of remediation. Crest and Redland continue to carry out the ‘Scavenge Pumping’ during these discussions.


This consultation is now closed. You can view the summary of the consultation and the responses under Related Documents the bottom of this page.

We have now served the remediation notice on the Appropriate Persons. If you would like a copy of this notice and the accompanying decision document please contact us at or on 03708 506 506.


St Leonard's Court, Sandridge, is a small residential development built in 1986-7. The land was previously used as a chemicals factory, manufacturing brominated compounds between approximately 1955 and 1980.

Aerial photograph of chemicals factory, Sandridge.

Aerial photo of chemicals factory, Sandridge

Historic contamination of this land has caused a plume of bromate and bromide in groundwater stretching approximately 20 kilometres from the source, impacting public and private water supply abstractions, and discharging via natural springs into the River Lee. Mean (average) bromate and bromide concentrations in natural waters are shown on the maps below.

Map displaying bromate concentrations in natural waters between January 2013 to December 2017.

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Map displaying bromide concentrations in natural waters between January 2013 to December 2017.

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Current management

The pollution is currently managed by scavenge pumping, which is a process whereby the contaminated groundwater is pumped from a closed public water supply well, treated and discharged to foul sewer. Groundwater from the other public water supply abstractions is blended to ensure it meets drinking water standards. The affected private water supply abstractions are restricted in their use.


Under the Environmental Protection Act 1990, Part IIA (PartIIA) and associated contaminated land regulations, St Leonard’s Court was determined as a contaminated land site by St Albans District Council on 20 June 2002. On 8 August 2002 it was designated a special site, thereby transferring responsibility for enforcement from the Council to the Environment Agency.

We identified the parties responsible for the pollution, called the Appropriate Persons under Part IIA, as two companies, Crest Nicholson Residential PLC (Crest) and Redland Minerals Limited (Redland). In 2005, we served a remediation notice on them. Both companies appealed against the notice. The appeal was heard at a public inquiry in 2007. The Secretary of State for the Environment issued a decision on 22 July 2009, upholding the actions of the notice that the Environment Agency recommended to the Inspector at the appeal hearing, but slightly varying the division of responsibility between Crest and Redland (the First Notice). The First Notice is appended to the Consultation Document.

Crest and Redland have so far completed 11 of the 12 actions in the First Notice. The remaining action is the ongoing procurement of the interim scavenge pumping from the well closed for public water supply. This action will expire on 21 July 2019. We are working to ensure the interim scavenge pumping does not cease on this date as it is essential in managing bromate and bromide concentrations at downstream public water supply wells.


The Appropriate Persons and the owners of any land to which the notice relates (the statutory consultees) have received hard copies of the consultation document. This represented the start of a statutory consultation period on the next phase of remedial actions as required by Section 78H(1)(b) of the Environmental Protection Act 1990.

This online consultation is to allow participation from others, including local interest groups, industry and academia.

The key documents can be found below under 'Related'. Copies of the supporting documents that are referenced within the Consultation Document but not provided here are available on request. Some documents are hard copy only and can only be viewed in person at the Environment Agency, Hertfordshire and North London area office. If you would like to view these please contact us to arrange a date and time. 

For any enquiries please contact the Customers and Engagement team, Hertfordshire and North London:

020 3025 9210
Environment Agency, Alchemy, Bessemer Road, Welwyn garden City, AL7 1HE

If you contact us by post please provide us with your relevant contact details.


  • Businesses
  • Charities
  • Statutory organisations
  • NGOs
  • Members of the public
  • Elected representatives, including MPs
  • Local councils
  • Academics
  • The nuclear industry
  • All water abstractors
  • Environment Agency customers


  • Water resources
  • Water quality