Property owners and managers have an effective marketing tool in the use of water purification systems as amenities. Owners and managers should have their water tested before selecting a purifier to determine the types of harmful chemicals and organisms that are in the water. Both local health agencies and Environmental Protection Agency-certified private laboratories conduct tests at a cost of about $25 to $100 for a basic test. Maintenance, which costs between $25 and $100 per year, is a good investment because it results in long-term reductions in the costs of plumbing fixtures and repairs. Property managers can choose from several types of purifiers, including reverse-osmosis units, distillers, and carbon filters.