A section of Hugh Street will be closed for emergency works to the mains water pipe on Sunday (June 9th).
Scilly's Council announced that the road between the Atlantic slipway and R Douglas Chemist will be inaccessible between 9am and 6pm while the job is carried out.
Residents in town may also experience some interruption to their water supply, as well as discoloured water after the job is complete.
The Council said in a statement: "During the works, there is a possibility that St Mary's public water customers from St Mary's Hall Hotel, through to the Garrison may experience some interruption to their water supply; however the Water Department will be aiming to carry out the work in such a way as to cause as little disruption as possible.
"Once the works have been undertaken, there may be some discolouration of the water. This is normal. White ‘milky’ appearing water (which clears on standing) is as a result of aeration to the water and can last several days. Any other discolouration is a disturbance of sediment which will only last a very short time and can be cleared by running your taps."
The statement added that the works are essential and although any interruption will be avoided as far as possible, the full scale and impact of the job cannot be anticipated.
Residents seeking more information are asked to contact the Infrastructure services team on 01720 424450 or email firstname.lastname@example.org.