Environmental health literacy (EHL) is defined as the understanding of how the environment can impact human health, yet there are few tools to quantify EHL. We adapted the Short Assessment of Health Literacy (SAHL) to create the Short Assessment of Environmental Health Literacy (SA-EHL). Using the Amazon mTurk platform, users (n = 864) completed the 18-item SAHL and the 17-item SA-EHL. The SA-EHL was originally tested with 30 items; 13 items were removed because they were outside the acceptable difficulty parameters (DIFF: −0.4–4.0) or because of limited variance (>90% correct or incorrect), resulting in the final 17 items. Overall, participants scored highly on the SAHL, with 89.9% exhibiting high literacy. In contrast, the majority had low EHL (<1.0% high literacy, 99.2% low literacy) measured by the SA-EHL. The two scales were not correlated with each other (R2 = 0.013) as measured via linear regression and dichotomous variables. Scores on the SAHL and the SA-EHL were positively correlated with education. The SAHL was positively correlated with age, gender and marital status, whereas the SA-EHL was not. The SA-EHL can be used to gauge EHL for communities, and the results used to improve interventions and research translation materials.