New Forest Catchment Partnership

Sunset on river at bucklers hard

Water Quality – phosphates

The New Forest Catchment partnership is working to help tackle the impacts of phosphorus-rich wastewater on our rivers.

Coming from the food we eat and the cleaning products we use, the waste water from our homes and businesses is rich in the nutrient phosphorus. Many smaller wastewater treatment works and all private systems (like septic tanks) don’t have the capability to remove phosphorus during treatment, resulting in it being discharged into our environment.

In the form phosphate it greatly impacts the natural balance of our waterways, as it feeds nutrient-hungry algae instead of the more wildlife friendly plants usually found in the Forest’s rivers. When the algae die and are deposited as sediment, it can smother plants and use up oygen as it decomposes, suffocating aquatic insects and fish.

A technique called source apportionment can be used to trace phosphate pollution in our waters to a particular source. Results for the New Forest show that wastewater treatment works, private sewerage, aquaculture and agriculture all contribute to phosphate pollution.

Our septic tank leaflet will help the owners of private sewerage to keep their systems in good order, preventing costly repair bills and avoiding environmental pollution. The leaflet combines the new national  ‘General Binding Rules’ with best practice advice to keep systems working effectively. In certain parts of the catchment, new systems will require a permit to ensure that they don’t pollute our rivers – check Government advice to find out where.

Households and businesses on mains drainage can also help to reduce their share of the impact, by limiting the amount of phosphate they contribute via domestic cleaning products. Some commonly used products, such as dishwasher tablets, can be up to a third phosphate and using alternatives can have a great benefit for wildlife. If you want to know more about phosphate pollution, read our phosphorus leaflet.

Meanwhile, other stakeholders are also taking action to protect the Forest’s waterbodies from phosphate pollution. Catchment Sensitive Farming officers work with farmers to help them reduce all types of Diffuse Water Pollution from Agriculture (DWPA) in order to protect our rivers. Check Government guidance for more information.

Water companies are also investing in upgrades to wastewater treatment works to enable them to more effectively remove phosphate from the water they receive. This can be cost effective for larger works and many have already been upgraded. It can be impractical or extremely expensive (impacting customer bills) to add this treatment at smaller works, so companies are involved in national trials to try to identify new means of undertaking removal at these more difficult sites.

  1. River catchment project
  2. About New Forest rivers and streams
  3. Helping our rivers and streams
  4. About New Forest Ponds
  5. Water Quality – phosphates (you are here)
  6. Case study: Lymington
  7. Case study: triops
  8. Contact us


image-fade-right image-fade-left