Tasks Read blueprints, drawings and specifications to determine layout of plumbing system, water supply network and waste and drainage systems Locate and mark positions for pipe connections, passage holes and fixtures in walls and floors Cut opening in walls and floors to accommodate pipe and pipe fittings Join pipes using couplings, clamps, screws, bolts, cement or soldering, brazing and welding equipment Test pipes for leaks using air and water pressure gauges Measure, cut, thread and bend pipes to required shape and size