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Byelaw 49 - Prohibition of discharge of sewage to the Thames

Guidance to Boat Owners on Compliance with Byelaw 49 – Prohibiting Discharge of Sewage into the Thames

1. Introduction

PLA Byelaw 49 comes into force on 1 January 2015. The Byelaw prevents the discharge of sewage into the Thames from specified vessels, consistent with the continuing improvement of the Thames environment, particularly with Thames Water’s project to stop the discharge of untreated sewage into the river, and brings the Thames into line with a number of other UK harbours and inland waterways.

For the purposes of this byelaw, sewage refers to faeces and urine plus any water associated with them.

The full text of the Port of London Authority Byelaw 49 is reproduced below:


49.1 The owner of:

a) a vessel licensed under section 124 of the Act or
b) a houseboat

must, from1 January 2015, ensure that no sewage is discharged into the Thames.

49.2 In this byelaw “houseboat” means any vessel (other than a ship registered under the Merchant Shipping Act 1995 or any vessel usually used for navigation) which is used primarily as a place of habitation, or as a place for accommodating or receiving persons for the purposes of shelter, recreation, entertainment or refreshment, or as club premises or offices, while it is moored.

2. Options to Comply with Byelaw 49

There are a number of options for a boat owner to comply with Byelaw 49 and these are outlined below:

a) Use Shore Facilities

Where practical, use shore facilities.

b) Plumb to sewer

We advise that any vessel occupier wishing to discharge to sewer contact the appropriate sewerage undertaker.

Contact details for all water companies can be found at the OFWAT website:

c) On-board treatment

There are a number of small scale treatment units available for use on boats that will treat sewage.

If you are considering installing such a treatment unit, you should comply with the following requirements:


  1. All works and equipment used for the treatment of sewage effluent and its discharge must comply with the relevant design and manufacturing standards (ie the British Standard BS EN 12566-3) that was in force at the time of the installation, and guidance issued by the appropriate authority on the capacity and installation of the equipment.
  2. The sewage must receive treatment from a sewage treatment plant.
  3. The sewage treatment plant system must be installed, operated and maintained in accordance with the manufacturer’s specification. This includes periodically removing waste sludge (to be done by an authorised person and disposed of to an appropriate facility).
  4. The discharge from a sewage treatment plant must not cause pollution of surface water or groundwater.
  5. For discharges from a sewage treatment plant in tidal waters, the discharge outlet must be below the low water mark.
  6. Maintenance of the sewage treatment plant must be undertaken by someone who is competent.
  7. The owner must ensure a sewage treatment plant system is appropriately decommissioned where it ceases to be in operation so that there is no risk of pollutants entering the river.
  8. If a vessel is sold, the owner must give the new owner a written notice stating that a small sewage treatment plant is present, giving a description of the waste water system and its maintenance requirements.
  9. New regular discharges from a sewage treatment plant in a fixed location may need further assessment if in, or within 500m of, a Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar site, biological Site of Special Scientific Interest (SSSI), aquatic local wildlife site, freshwater pearl mussel population, designated bathing water, protected shellfish water or within 50m of a chalk river.
  10. New discharges from a sewage treatment plant must be made to a watercourse that normally has flow throughout the year.

(from EA General Binding Rules on Registration of Small Sewage Discharges - https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/367015/ssd-general-binding-rules-oct2014.pdf ).

Much guidance for small sewage treatment plants is for land-based applications but contains some information that may be relevant to design of plants for vessels:

d) Compost Toilets

Compost Toilets separate solid and liquid waste so that the solid waste breaks down under aerobic conditions to 10-30% of its original volume. The liquid element is still “sewage” and must not be discharged to water or within 10m of a watercourse. A large advantage of compost toilets is that they do not consume water.

There are currently no British or European Standards covering Composting Toilets (http://www.planningportal.gov.uk/uploads/br/100312_app_doc_G_2010.pdf). The Environment Agency Pollution Prevention Guideline Number 4 (PPG4) on treatment and disposal of sewage where no foul sewer is available (https://www.gov.uk/government/collections/pollution-prevention-guidance-ppg) notes that the fluid fertiliser (urine) and dry compost (faecal matter broken-down under aerobic conditions) should not be discharged to a watercourse.

We recommend that you read the Environment Agency position statement on using composting toilets and the resulting compost:

e) Install tank and routinely pump-out to a suitable receiver

Installation of a tank will necessitate this being pumped out to a suitable facility.

We have provided below a list of commercial sources of information and commercial providers of pump-out facilities. Provision of this information does not imply endorsement. We recommend that you contact the relevant provider for further information.

Pump Out Collection

There are currently no operators on the river who will come to a moored boat to pump out their tanks. It is expected that this situation will change and this note will be updated regularly to reflect any developments.

Pump Out Facilities

i) Canal and River Trust

The Canal and River Trust have two pump-out facilities that are located close to the Thames. These are located at (tbc):

Further details are available from the Canals and River Trust (https://canalrivertrust.org.uk/boating/navigating-the-waterways/services-for-boats/water-points-and-sewage-disposal) with boating facilities shown on a map at https://canalrivertrust.org.uk/in-your-area?q=london#lat:51.503700011096726,lng:-0.16127620054365188,zoom:12 and searchable as “boat services”.

ii) The Green Blue Website

The Green Blue website (http://thegreenblue.org.uk/Pump-Out-Directory) has a list of pump out facilities on the Thames.

iii) Facilities in nearby areas

iv) Other

Details are also available on the Boating on the Thames and Port of London Authority websites:

3. Grey Water

Byelaw 49 applies only to Sewage (also known as black water), but the discharge from your sinks (also known as grey water) can also have a detrimental effect on the environment.

The Green Blue website has further details about the effects of detergents, washing up liquids and soaps on the aquatic environment. We recommend that only phosphate-free detergents are used, and advise that you use environmentally-sensitive washing products where possible.

If possible, re-plumb waste water systems so that both grey and black water are diverted to the holding tank and then disposed of by one of the methods outline above.

4. Further Information

The Green Blue has produced a Fact Sheet on the impact of the discharge of grey and black waters on water quality. It can be found at the following webpage:

5. Guidance to Companies looking to provide a Sewage-Away Service

Guidance will be published here shortly.

All information provided herein is current at the time of publication. Inclusion in this guidance does not imply endorsement by the PLA.

Download:Byelaw 49 - Prohibition of discharge of sewage to the Thames