During replacement of a sprinkler head, dirty black water was observed flowing from the sprinkler line. This happens due to rust formation, stagnant water, lack of flushing, and poor maintenance of the system. As per IS 15105 and National Building Code 2016, fire sprinkler systems must be properly inspected, tested, and maintained at regular intervals. Sprinkler pipes and heads should be checked for corrosion, blockages, and replaced or cleaned as required. Hydrostatic testing, flushing of lines