University College Dublin's Estates division 'sincerely apologised' to residents who had waste water accidentally pumped into their toilets in November.
Just trace amounts of foul water were included, but that could still contain parasites, bacteria or viruses.
These could potentially get caught in aerosols and droplets.
The UCD University Observer reports 60 apartments were affected, and all bathrooms are to be deep cleaned as a result.
In an article the paper also reports students were given a €30 voucher as a form of compensation.
Pretty gnarly story I reported for the UO. Hope you've all got strong stomachs. https://t.co/9zF0Lf6MpL
— Michael Bergin (@batmanbergins) January 25, 2022
The Estates division sent an email to residents in December, outlining what had happened.
It says "the likelihood of you having been infected by these organisms is very low for a number of reasons primarily as the water is used for flushing toilets only and is not directly ingested."
However it committed to 'fogging' bathrooms with disinfectant - that's essentially a deep clean.
The email also advised residents to bin toothbrushes or toothbrush heads, and wash towels or robes at 60c separately with detergent.
Anyone with symptoms or gastro-intestinal problems was advised to contact residence operations.
Those with compromised immune systems were told to be 'vigilant.'