Cu-CHA combine high activity for the SCR reaction with better hydrothermal stability and selectivity compared to other copper substituted zeolites. At the same time Cu-CHA offers an opportunity for unraveling the coordination environment of the copper centers since the zeolite framework is very simple with only one crystallographically independent tetrahedral site (T-site). In this study the results of an X-band EPR investigation of ion exchanged Cu-CHA zeolite with a Si/Al ratio of 14±1 is presented. Different dehydration treatments and rehydration experiments are performed in-situ while monitoring with EPR. The results are compared with recent literature evidence from temperature programmed reduction, X-ray methods, IR spectroscopic methods and UV-visible spectroscopy. Based on these findings quantitative information is obtained for the different copper positions in dehydrated Cu-CHA. The well-defined copper sites in the 6-membered ring of the CHA structure are found to be EPR active, to give two distinct sets of signals in an approximate 1:1 ratio and add up to 19±2 % of the total copper in the material. The long-standing question of the EPR silent monomeric Cu2+ in copper substituted zeolites is suggested to be copper species with an approximate trigonal coordination sphere appearing during the dehydration. After complete dehydration at 250 °C the majority of the EPR silent Cu2+ are suggested to exist as Cu2+-OH− coordinated to two framework oxygen atoms located in the microenvironment of an isolated Al T-site.