Water Affordability Act This bill amends the Federal Water Pollution Control Act (commonly known as the Clean Water Act) to require the Environmental Protection Agency to establish a pilot program that awards grants to at least 10 eligible entities to improve the access of low-income and environmentally at-risk households to sanitation and drinking water services. In order to be eligible for grants, entities must be municipalities, or public entities that own or operate public water systems, that are affected by consent decrees related to compliance with standards under that Act.