The company which stops Sydney's sewers from stinking too much is sniffing out an ASX listing in the next 12 months.

Calix made $3.6 million in 2016-17 selling a compound which it claims is neutralising sulphuric acid in 90 per cent of Sydney's wastewater pipes, not only stopping concrete corrosion but the production of gas which unchecked would "stink unbearably", according to managing director Phil Hodgson.