I have been living in a villa in Jumeirah 1 for over 2 years and wonder if I should ever get the water tank cleaned?

Yes you should as these water tanks are ideal breeding grounds for all types of diseases. This is where most of the water we use in the house comes from and if left for long periods will cause mold and other bacteria to grow.  Many water tanks in older villas have ill fitting lids or the lids may have fallen off completely allowing insects, leaves etc to fall in to the water tank.  Water tanks should be cleaned out yearly and you should use a Dubai Municipality Approved company to make sure it is done properly.  The entire tank should be drained, broken lids replaced, the walls scrubbed with an approved disinfectant, thoroughly rinsed out and dried completely before refilling.  Make sure you check the job that has been done.