The infrastructure deficit is the gap between investment needed to maintain infrastructure in good condition and actual investment levels—essentially the accumulated backlog of deferred maintenance, delayed repairs, and needed replacements. The Federation of Canadian Municipalities estimates the municipal infrastructure deficit at hundreds of billions of dollars. Causes include: decades of underinvestment, aging infrastructure nearing end-of-life, deferred maintenance accumulating larger problems, downloading of responsibilities without adequate funding, and construction of new infrastructure without providing for lifecycle costs. The deficit manifests in deteriorating roads, water main breaks, aging treatment plants, and facilities needing replacement. Addressing the deficit requires increased investment from all orders of government, improved asset management practices, and difficult decisions about priorities. Climate change is adding pressure as infrastructure must be adapted to new conditions. The infrastructure deficit represents one of the most significant challenges facing Canadian municipalities.