Colorado health officials are considering whether to eliminate requirements to monitor and treat groundwater now being discharged from large commercial structures, saying the regulations add too much cost to business operations and to new construction projects, including affordable housing developments. The water can come from a variety of sources, including underground parking structures and elevator shafts. Roughly 100 such “dewatering systems,” as they are called, now operate in the state, according to the Colorado Department of Public Health and Environment, with the majority in urban areas, such as downtown Denver and Cherry Creek. Environmentalists, however, are sounding the alarm, saying the water is often highly contaminated and, if it is allowed to percolate through soils without treatment, will make its way to rivers, such as the South Platte, causing more serious contamination by adding more pollutants to streams already tainted by arsenic and a group of chemicals known as PFAS.