Water systems which create and disseminate breathable water droplets or aerosol present the highest risk of contracting Legionellosis. The degree of risk is affected by general cleanliness of shower heads, water temperature control and design flaws such as dead legs or long runs of pipework. Quarterly clean and disinfectants of spray heads and hoses can help prevent and control this risk.
While spray and fine droplets will always be present as water hits the sink, however, this risk is escalated by the use of spray nozzles which increase the risk of Legionella proliferation.
Indeed, any fog/mist/spray of water droplets are classed as a Legionella risk. This newspaper report summarises a well-publicised outbreak at The Playboy Mansion in Los Angeles, which was caused by a fog/mist machine used at a party.