An environmental law specialist is warning dairy farmers they risk face tougher penalties if their  effluent systems don’t work properly .

Hans van der Wal from Duncan Cotterill successfully prosecuted several  illegal dairy effluent discharges.

He says councils and the courts are coming down harder on farmers who break the rules. And he says farm owners also need to make sure that sharemilkers and farm labourers know how the effluent systems  work.