The Environment Agency has recently released a map showing where Combined Sewer Overflows (CSO) have released sewage into water courses. Plymouth Live published it here https://www.plymouthherald.co.uk/news/plymouth-news/every-plymouth-sewage-hotspot-near-8552351
From this, we can see that a CSO behind Cheshire Drive last year had 13 spills and released sewage into the stream for an equivalent of 6 days. Tamerton Foliot Sewage Pumping Station on Station Road is also a CSO which had 32 spills releasing sewage for 71 hours.
These are licensed releases. In addition problems continue with the manole in Church Row Lane, and in the fields towards Coombe Lane.