Water quality and commissioning

Disinfecting and water quality testing 

Once your new main has been laid you can pressure test and disinfect it. You need to let us know before this happens so that our engineer has the option to witness it.

We’re now charging for taking water quality samples. The cost for this will be £118.26 (plus VAT) per visit and a further £65.63 (plus VAT) per sample analysed. Please note that we’ll only carry out analysis on samples that we have taken.

Under the 2017 revised National Code of Practice for Self-Lay, you’re now able to take water quality samples and ask a laboratory of your choice to analyse them. The Energy and Utility Skills Register (EUSR) are in the course of setting up a training module, to provide a national accreditation.

If you wish to take your own samples in the meantime and avoid being charged, we’ve set up our own interim accreditation. This is free and valid for 12 months, by which time an EUSR scheme should be in place. If you’d like us to train and assess your staff, please email selflay@thameswater.co.uk to book an appointment.

We’ll require your staff to take bacteriological samples from a 25mm standpipe fitted with a gunmetal bib-tap which does not have an in-line check valve assembly – so please check this before making an appointment.

We recommend that your teams are equipped with turbidity meters, so that this can be checked on site. This should prevent the laboratory you use from failing a sample because the turbidity is too high, which could cause you delays. 

We also recommend that samples are kept between 3⁰C and 7⁰C during transit, in either a compact fridge or cool box which does not share space with food and drink.

We only require tests for coliforms, E.coli, taste, odour and turbidity, as per Principles of Water Supply Hygiene. Testing must be carried out by a UKAS accredited laboratory. The quantity of water required for analysis and the bottle types will be dictated by the laboratory used.

As noted above, our own laboratories in Reading cannot provide this service, and will only test samples that we have taken.

Connecting the main

Once your water quality samples have been passed, you can start to plan the permanent connection. We can carry out this connection for you but you can do this ‘routine mains connection’ yourself (as long as there's no water supply interruption to customers, or other risks, and you have the correct accreditation). We'll need a copy of the pressure test result and chlorination certificate before your mains connection is authorised.

When you apply to connect to our network, you need to provide us with your 'plot to connection' programme. We'll use this to monitor when you're due to connect any non-household properties.

You'll need to appoint a retailer for each of these before connecting them. If not, we'll inform the Market Operator that a connection is imminent, and they will appoint a retailer on your behalf. More information can be found in our News and Improvements section.

Non-household properties

When you apply to connect to our network, you need to provide us with your 'plot to connection' programme. We'll use this to monitor when you're due to connect any non-household properties.

You'll need to appoint a retailer for each of these before connecting them. If not, we'll inform the Market Operator that a connection is imminent, and they'll appoint a retailer on your behalf. More information can be found in our News and Improvements section.

Quality assurance

Once you've laid the water mains and associated fittings, we'll check it has been installed to the approved design and specification, and that your operatives hold the required training and accreditation cards. It's important that you keep to our standards, as defective work will require correcting, which can cause delays.

Service connections and Water Regulations inspections

If you’re connecting service pipes to the new main, each plot on the development will need a Water Regulations inspection. We'll carry out this inspection for you, unless we’ve trained your staff to make these inspections or you're employing an approved plumber - see our approved plumbers list. They will provide you with a certificate which you need to send us to let us know when the connection has been made. You can then complete the connection and fit the meter at a time which suits you.

If there are non-household properties on your development, you'll need to have appointed a retailer for each one before making the connection.