The location of sewer lines and or existing drains often gets overlooked when plans are drawn up for new structures or alterations and/or extensions. This may lead to more pressure on the existing drainage network than it can handle which in turn will lead to numerous expensive call-outs for plumbers.
Roof surfaces, surface water and waste water disposal is just a few of the factors that needs to be taken into consideration when doing any contractual work.
Re-development of areas also creates potential problems as the existing infrastructure rarely can provide for group or cluster housing and in order to save costs the existing structure rarely gets upgraded.
The best and only way to avoid disputes later on, is to appoint the qualified plumbers and drainage engineers from inception of the project. Remember your building contractor is knowledgeable about building work, but not necessarily about plumbing/drainage work.