Leavesden and Meriden are ranked in the top 20 per cent of unhealthiest areas in the UK.
Researchers have put together an interactive map which shows which areas are healthy and unhealthy around Watford.
The map shows that Garston falls in the medium category of unhealthiest areas, it shows that the areas hit slightly worse are near Leavesden and Meriden.
The map, created by researchers from the Consumer Data Research Centre (CDRC) analysed air quality, access to green space and access to health services among other criteria to find out the unhealthiest areas.
Living close to ‘unhealthy’ retail services such as takeaways, pubs and gambling shops have also been considered.
Other areas including West Watford, Oxhey and Croxley Green fall within the best performing ten per cent places in the UK.
If you want to know more about your area, you can view the results on the interactive map.