Having a rain barrel underneath your roof’s downspout allows you to collect rainwater that can be used to water your yard (and lower your water bill). Via this City program, you may purchase a rain barrel for $72.70 plus tax, at a 40 percent discount from the usual barrel price of $119.95. Order your rain barrel in advance at http://www.nerainbarrel.com/ and come pick it up on May 14 at the DPW. Rain barrels are 3 feet tall and 2 feet in diameter. They hold up to 60 gallons of water. When/Where: Between 9 a.m. and noon at the DPW Yard at One Franey Road. Orders must be placed by May 11. Contact: Somerville Office of Sustainability at firstname.lastname@example.org or 617-625-6600 ext.5070. Or, New England Rain Barrel at 1-877-977-3135.