Rainfall harvesting for artificial recharge is an option to address water scarcity in Gaza, which has an average annual rainfall of 350 mm and will also reduce urban flooding. Continuous urban expansion has increased runoff and decreased natural infiltration in open areas. This study examines the quality of collected storm water from rooftop and streets to mitigate any risk reveals. Collection of stormwater runoff from rooftops and diverting it into local infiltration systems for artificial recharge to groundwater will also decrease road flooding in the city. The quality of harvested rooftop stormwater runoff in Gaza has proved to be suitable for artificial recharge and meets drinking water standards. The harvested stormwater has low concentrations of chloride and nitrate and as groundwater recharge will improve the quality of the existing brackish groundwater. The risk of heavy metal contamination of groundwater is low, since the measured pH in all rainwater runoff was close to 7.0. This reduces the risk of solution and mobilization of heavy metals in the infiltrating water.