To find out whether or not you are eligible for a self-certified agreement, complete the questionnaire on the Thames Water Build Over website (link above). Or ask us! All pipes near the site can impact the design, so it`s best to know where the pipes are if you`re planning to avoid delays and additional costs. If you`re not sure how to do it, we`re here to help. For more information about related and unasyed pipes, see below. A Thames Water Build Over agreement is a quality label for the proposed work and is usually required for all excavation work within 3 meters of a public sewer or sewer. Don`t worry, just fill in as many details of the app as possible, even if they are very simple. Take a look at your communal offices and take a look at their canal maps.