1) The document discusses two types of drainage systems: combined and separate. The combined system uses one set of pipes to convey foul and surface water together while the separate system uses two sets of pipes. 2) It provides details on good drainage practices such as using materials that are smooth, hard, and non-corrosive and laying pipes at appropriate slopes for self-cleansing flow. Joints must be air and water tight. 3) Flexible independent rubber ring joints are discussed as having advantages for push-fit assembly, ability to assemble in wet conditions without lubricants, and accommodating ground movement while preventing root penetration.