Section 161 of the Water Resources Act 1991 currently enables the Environment Agency to undertake clean up actions where it appears to them that any poisonous, noxious or polluting matter or any solid waste is likely to enter or has already entered controlled waters. The Agency can then undertake works to prevent pollution and can then recover the costs of doing this from any person who either caused or knowingly permitted the matter in question to be present at a place from which it was likely to enter controlled waters or who caused or knowingly permitted the matter in question to be present in any controlled waters. Section 161 is not therefore, limited to those who actually caused the pollution themselves. Even if a person or company allows waste or pollutants to remain at a place where they are likely in the future to cause a problem, they/it may still be liable for clean up costs.

The Environment Agency has pursued very few actions under Section 161. This is mostly due to the fact that the Agency has to undertake the work itself and then attempt the difficult task of retrieving the costs. The EA 1995 now amends the Water Resources Act 1991 and allows the Environment Agency to serve works notices on the parties responsible requiring clean up of the controlled waters, and thus does not have to undertake clean up operations itself. Failure to comply with a works notice is a criminal offence and can incur a fine. The Agency can clean up themselves and then chase the person who has not complied with the notice. As the scope of controlled waters is wide in the legislation, the Agency could use the provision more frequently and, as many have observed, use it in enforcing the remediation of contaminated land. Company's should take note of this particularly if they are planning to undertake water and contaminated land audits.