Estádio Municipal José Batista Pereira Fernandes (Distrital do Inamar / Arena Inamar)

The ground in Jardim Inamar started out as a bare training pitch, Campo do Inamar, opened on 22 May 2009 with room for 5,000 at amateur tournaments. It only became a proper municipal stadium in December 2012, when a rebuild costing roughly 5 million reals — part of a wider 12–15 million real development — added concrete stands and gave the ground its present name, honouring José Batista Pereira Fernandes, a Diadema community figure and founder of a local cultural centre, who died that same year.

That 2012 rebuild also laid a FIFA-standard synthetic pitch, but the club had it torn up within a year and replaced with natural grass. The roof and full floodlighting sketched into the original project were never built.

The bowl holds 10,000, yet the São Paulo state federation, the FPF, capped attendance at 8,075 after a 2015 safety inspection — a gap that says more about the terracing than the turnstiles. The highest crowd on record came on 10 April 2016: 7,283 for a Campeonato Paulista Série A1 fixture against São Bernardo, which Água Santa lost 0-1. No match since has drawn more.

Água Santa have used the arena as their home since 2012, taking over the tenancy from Clube Atlético Diadema, who played there until 2019.