If you are buying a complex built prior to 1973 it will more than likely have cast iron waste lines. Cast iron pipes often have internal corrosion that results in leaking and clogging, or cracks that cause leaking within the units. Soil PH and corrosive chemicals and detergents put down the drains can cause the pipes to fail prematurely, Tree roots are another condition that can damage these pipes. Cast iron is stilled used today and is very durable. The problems is not so much the cast iron, but the age. Everything has a life expectancy and cast iron pipes are no different . We have inspected many properties with cast iron that had no issues at all.
Be sure to ask the seller, maintenance staff, and tenants about any past or current drainage problems. You can get a wealth of information talking with tenants and the maintenance staff. If the seller tells you the cast iron has been replaced from the building to the street…keep in mind there’s usually still cast iron within the slab and wall space and this is where problems can still occur.
Having an in-line camera inspection performed on the property during your due diligence period can save you tens of thousand of dollars in costly repairs and lost revenue. Also during your property inspection, the inspector should flow lots of water and stress the system to ensure proper drainage.
Detecting failing waste lines during your due diligence is the best outcome. And having the proper inspections is your best defense.