Drainage blockages and toilet obstructions:
constitute the most commonly reported plumbing service requests.
Changes made:
Enhanced formality by replacing "blocked drains and toilets" with "drainage blockages and toilet obstructions"
Changed "represent" to "constitute" for more professional language
Replaced "frequently requested" with "commonly reported" to elevate the tone
Modified "plumbing services" to "plumbing service requests" for greater precision and professionalism
