According to the WHO, tap water is safe for consumption for 75% of the country.
There is a divide between rural and urban areas, tap water is safe to drink in 85% of urban areas, while it's only safe to drink in 58% of rural areas.
It's generally advisable not to drink tap water anywhere in Ecuador. Bottled water is widely available, and some hotels and guesthouses catering to foreigners provide purified water (agua purificada) for guests wishing to fill their own bottles.
According to the CDC tap water is generally not safe for consumption.
According to the Numbeo water drinkability and accessibility index, tap water has a score of 63.93 / 100 (100 being best).
Numbeo considers this score to be "High"
1 adult could save about 774$ per year in Ecuador by drinking tap water instead of buying bottled water.
๐ณ Drinking tap water would also help with reducing your plastic footprint and improve environmental pollution.
Like in most countries, water quality and accessibility differs from location to location, therefore it's the best to check the information available on that place.