
When it comes to the inside of the structure then according to building regulations a new conservatory should not contain any sinks or drains unless there is planning permission for a kitchen or extra bathroom. Neither should a conservatory be built over drains as this can cause problems - you should not be blocking access to any inspection chambers. An inspection chamber is where a professional can gain access to drains and underground sewers if there is a problem or the drain is blocked.
Where you build may also be governed by whether you have a private or a public sewer system i.e. one that is owned by your local authority. You should consult your local authority if you are unsure as to whether your sewage system is private or public. If the sewage system is public then there is a legal requirement for you to contact the local authority and ask whether they will grant approval for the conservatory to be placed where you had planned.
The same thing applies with inspection chamber covers. If you build over the cover then again this could cause problems and will mean that you may have to adapt your flooring to accommodate the cover. Again, these problems can be avoided if the conservatory boundary stops short of the inspection chamber and its cover.
Problems with drains and inspection chambers often happen when people want to build their conservatory next to the kitchen. In order to avoid having to obtain building permission a viable alternative is to have an external grade door between the kitchen and the conservatory. It is best to get a number of quotes for the work and to take the advice that your builder gives you.