Cyufjy

To add yet another question to the long list of tap-water, the US CDC for the Dominican Republic says Don’t Drink Tap or well water, but there is no mention of water concerns on gov.uk for the DR. The US warning is not everywhere (e.g., according the the CDC for the UK Food and water standards in the United Kingdom are similar to those in the United States) and gov.uk for Mexico says Drink only boiled or bottled water and avoid ice in drinks.

I am staying at an all inclusive high end resort in the DR. Avoiding drinking tap water directly should not be that hard, but ice and unwashed or unpeeled fruits and vegetables (which the CDC recommends against will be harder). I have heard rumors that some resorts use filtered water for cooking and ice.

How can I reliable determine if I need to worry about water at a resort in the DR?

It seems from the CDC's details page on DR that their concerns boil (sorry) down to two main issues, both of which you should be ok with if you've had your vaccinations - Hep A, and Typhoid.

It's worth noting that the Australian Smart Traveller website has a concern about cholera as well:

Cholera and other infectious diseases

Confirmed cholera cases continue to be reported in the Dominican
Republic. Cholera causes diarrhoea and vomiting and can be fatal if
left untreated. Correct food hygiene and preparation are essential to
minimise the risk of contracting cholera. Water-borne, food-borne,
parasitic and other infectious diseases (including hepatitis,
filariasis, and leptospirosis) are prevalent, with serious outbreaks
occurring from time to time.

Drink only bottled or boiled water.
Avoid ice cubes.
Avoid uncooked and undercooked food.
Ensure correct food hygiene and preparation.