Probably has phosphodiesterase (PDE) activity against cyclic-di-AMP (c-di-AMP); may be the major c-di-AMP PDE in the cell (PubMed:26240071). In B.subtilis c-di-AMP is a second messenger that mediates growth, DNA repair and cell wall homeostasis; it is toxic when present in excess (PubMed:26240071). 3',3'-c-di-AMP + H2O = 5'-O-phosphonoadenylyl-(3'->5')-adenosine + H(+) In strain 168 grown in minimal medium and glutamate, 3.5-fold increase in c-di-AMP levels, while a double pgpH-gdpP mutant has 4.2-fold increased levels of in c-di-AMP; double mutants die on solid medium after 2 days (PubMed:26240071). Belongs to the PgpH phosphodiesterase family.