The location of the pipes is equally important in the drainage system. Following need to be kept in mind.

1. Make sure that soil and waste pipes are erected before the laying of DPC (damp proof course), while rain water pipes are erected after the laying of DPC. Always decide the location of soil and waste pipes very carefully. A soil pipe too close to the corner may create a lot of problem in fixing of P1 trap to it.
2. Seat size, its   placement, and the distance of its centerline from the wall will determine
where a pipe should be located and embedded.
3. While installing PVC pipes with sockets, keep the sockets against the direction of the flow.
4. The joints in CI sanitary pipes are filled with lead. The joints in CI rain water pipes may however be filled with cement mortar. Repaired finishing never attains the same look that it had originally. It is better to ensure leak-proof and airtight joints.

Quality is also important to be retained in the system. Soft and pure pig lead that is free of all impurities should be used for lead joints. Don’t save on the cost of lead, nor allow   your   plumber to do that.  Always choose ISO 782   marked lead. Ask your plumber to make a sample joint of two spare cut pieces of pipe. When the lead has hardened, break open this joint, take out the lead and check its weight. If the weight is correct, two things will become known. First, the pipe sockets are fine and second, the plumber can make the joints correctly.

SOME PRECAUTIONS
1. While erecting sanitary pipes, fittings are to be inserted in them at various locations to connect floor traps and horizontal pipes at later stages when the flooring work is done and sanitary appliances are fitted.

2. Plug the open mouths of all the fittings and pipes with gunny bags to avoid their blockage till the cement (powder) by weight to form a cream like paste. Apply two coats of it with a brush on the slab surface. It can be applied even on a wet slab. Apply it on the walls and up to a height of six inch above the bathroom floor level.

3. Mark positions of pipes erected and mark them in red in an extra print of the plan.

4. Mark light colored lines on the surface of the walls of bathrooms and toilets along
the concealed PVC pipe lines.

5. Besides keeping the pipe joints water-tight, give the floors waterproofing treatment. On the sunken floors of toilets with Indian seats, apply flexible waterproofing membrane.

6. Prefer concealed plumbing over the conventional exposed plumbing as it enhances the aesthetics of your bathroom and creates space, making it easier to clean and maintain the bathroom and also there is less chance of damage to the pipeline.

7. The best solution is to insulate the pipe, using insulating threads or foams.

8. Use better traps with good water seals and have a separate drain for your washing machine. Frequent cleaning of traps will reduce the clogging problem.

9. Install a separate drain for the washing machine.