 Quicker and lower-cost methods, such as rubber sleeve joints, have largely replaced leaded hub connections of cast-iron piping in most new installations, but the older technology may still be used for some repairs.In addition, some conservative plumbing codes still require leaded hub joints for final connections where the sewer main leaves a building.Cast iron DWV pipe and fittings are still used in premium construction because they muffle the sound of wastewater rushing through them, but today they are rarely joined with traditional lead joints.