Previous research by Nickerson (2007a) testing 13 email get-out-the-vote (GOTV) campaigns concludes that email from third parties is not an effective method of increasing voter turnout. We conducted three rounds of email GOTV experiments in San Mateo County, California, in cooperation with the local registrar, the elected official responsible for administering elections. Unsolicited emails sent from the registrar consistently increased turnout among registered voters. The treatment effects are small, but statistically significant. In contrast, identical messages sent from a fictional voter mobilization organization had no measurable effect, consistent with Nickerson's results. We conclude that email sent from an official source can in fact be a cost-effective method of increasing turnout.