Cast iron and ductile iron pipe was long a lower-cost alternative to copper, before the advent of durable plastic materials but special non-conductive fittings must be used where transitions are to be made to other metallic pipes, except for terminal fittings, in order to avoid corrosion owing to electrochemical reactions between dissimilar metals (see galvanic cell).
General employment within the construction sector is sensitive to changes in the economy. But job growth for plumbers is projected to be faster than the average for all jobs. New buildings and residences are being built to comply with stricter water efficiency standards and companies housed in older structures are hoping to retrofit to use more energy-efficient systems, so opportunities are in abundance. According to the Bureau of Labor Statistics, there should be a hiring spurt of 16 percent for plumbers by the year 2026, which translates to about 75,800 new jobs.