- Nearly 4 marathons
Source: Environment Agency and Natural Resources Wales; England and Wales, April 2015 - March 2016
Percentage of rivers at good or better overall status; Source: Environment Agency and Natural Resources Wales; Jan 2015 - Dec 2015
Water quality in rivers and lakes is tested and given a rating of poor, moderate, good or high. The tests are for various things including:
- if chemicals in the water are below allowed limits
- how well the water flows
- how much wildlife (fish and river plants) are present in and around the waters
The tests have recently been made even tougher. The scoring system is such that even if the river fails just one of the many tests, it can’t be rated good.
Water companies treat sewage and once all the solids are taken out, the remaining wastewater is cleaned and put into rivers. The water companies have to work to meet very high standards and there is strong regulation.
The water quality in rivers can be badly affected by water flowing into them from farms and factories. This water can contain pesticides and chemicals.
Bacteria in the water can come from a number of sources, but the three main sources are: water draining from farms and towns during heavy rain; untreated sewage mixed with rainwater filling the system and overflowing into rivers (to prevent homes from flooding); and homes and businesses draining dirty water into the wrong pipes.