The objective of this study was to quantify the exposure reduction that could be achieved through the use of a water spray attachment while breaking concrete with jackhammers. The effectiveness of the water spray examined in this study was evaluated by measuring the reduction in the respirable dust and quartz exposures in the breathing zones of two construction workers when the dust control device was used compared to the exposure when no dust control device was used. Respirable dust exposure was measured in real time using a portable laser photometer. In addition, personal breathing zone samples for respirable dust and respirable crystalline silica were collected and analyzed using established NIOSH methods. Water applied using a solid cone nozzle at a flow rate of 300 mL of water per minute resulted in a 69 to 71% reduction in respirable dust exposure and a 77% reduction in quartz exposure. A water flow rate of 250 mL/minute resulted in a 42 to 43% reduction in respirable dust exposure and a 39% reduction in silica exposure. Use of the control with a clogged nozzle resulted in exposure increases. The best exposure reduction demonstrated in these trials would permit a worker to use the jackhammer under these conditions for up to 4 hours and 45 minutes in an eight-hour shift with no other exposures to quartz without exceeding the REL or up to 6 hours and 40 minutes in an eight-hour shift with no other quartz exposures without exceeding the calculated OSHA PEL.