Britain’s rivers are an essential source of fresh water for drinking, agriculture and industry. In addition, they play a crucial role in maintaining biodiversity and are a valuable recreational resource. However, urbanisation, population growth and climate change are creating an unsustainable burden on our rivers and are having a continuing detrimental effect on water quality. A report by the World Wildlife Fund (WWF) recently found that four out of five rivers (80%) in England and Wales fail to achieve ‘good ecological status’ and that 55% of all rivers in England and Wales failing to reach the required 'good ecological status' are polluted by waste water.
High levels of nutrients [Nitrogen (N) and Phosphorus (P)] can cause pollution in rivers and lakes and impact on biodiversity and water quality. N and P pollution is often a consequence of human activity. For example, N and P are applied to agricultural land to support profitable and competitive farm enterprises. However, due to a combination of land management practices, land vulnerability and climatic factors, losses of nutrients from agricultural land is a key contributor to the pollution of surface and ground waters. Agriculture, however, is not the only contributor. Urban and point sources of pollution, including effluents from sewage treatment works, also contribute to the pollution of these water bodies with N and P.
Excessive nutrient content encourages the growth of plankton, which can over-shade or suffocate fish and other plants. In extreme cases, it can lead to blooms of toxic algae harmful to humans and animals.
Water quality in Herefordshire
Mains water in Herefordshire is supplied by Welsh Water (Dwr Cymru) and in part by Severn Trent Water. Between 5 and 10% of Herefordshire's population use a private water supply for domestic purposes.
Most of Herefordshire is in the catchment of the River Wye and its waters are a measure of the health of the county’s environment. A lot of our drinking water comes from the river and its tributaries. 
The River Wye is one of the Britain’s largest rivers, rising on the Plynlimon Mountains at 741m AOD and flowing through several towns including Rhayader, Builth Wells, Hay-on-Wye, Hereford, Ross-on-Wye and Monmouth before meeting the Severn Estuary at Chepstow. The total catchment area is 4136 km2. The Wye is one of the most important rivers in Britain for nature conservation and much of the lower valley is an Area of Outstanding Natural Beauty. The Wye is one of the best known salmon rivers in England and Wales. Shad and Sea Lamprey also migrate into the Wye. The river corridor also supports a variety of plant communities, otters, water voles, several bat species, dippers, sand martins, kingfishers and little ringed plovers. The biological quality of the river is generally good and supports several rare or scarce species including the mayfly Potamanthus luteus , the freshwater pearl mussel Margaritifera margaritifera and the native crayfish. The river also supports several rare species of non-aquatic invertebrates associated with gravel shoals.
In Herefordshire, the River Wye has a high level of protection under European law as a Special Area of Conservation (SAC). This includes the River Lugg tributary as far as Hope-under-Dinmore. The Environment Agency (EA) regularly checks phosphate levels in the SAC, and the tributaries that feed into it, to ensure that they stay within agreed ceilings.
A Nutrient Management Plan (NMP) is in place to enable the desired economic growth in Herefordshire whilst achieving and maintaining Favourable Condition Status for the River Wye SAC. However, phosphate levels in some sections of the River Wye SAC as a result of controlled waste water discharges associated with residential and industrial developments and agricultural practices in the catchment area are a concern (especially for the River Lugg ) and are degrading the ecosystem. 
 Flushed away: How sewage is still polluting the rivers of England and Wales, H. Blackburn, R. O’Neill and C. Rangeley-Wilson, World Wildlife Fund, 2017.
 Updating the Estimate of the Sources of P in UK Waters - WT0701CSF, Department for the Environment, Food and Rural Affairs (DeFRA).
 Water Quality and the Nutrient Management Plan, Campaign to Protect Rural England Herefordshire.
 Wye, UK Environmental Change Network
 River Wye SAC Nutrient Management Plan Action Plan, Environment Agency and Natural England, 2014.
 Herefordshire Local Plan Core Strategy 2011 – 2031, Herefordshire Council, 2015.
 River Wye SAC Nutrient Management Plan Evidence base and options appraisal, C. Allaway, Atkins Global, 2014.
- CPRE Herefordshire - phosphate map
- Environment Agency catchment data explorer – Wye management catchment
- Herefordshire Council - adopted core strategy
- Herefordshire Council - water supplies
- Nutrient Management Plan: River Wye
- Severn Trent Water – check my water quality
- Welsh Water – in your area – water quality