Guatemala Water Can I drink the water from the faucet if I use a sawyer (water filter) or should I still stick to bottled water?

I went to  Quetzaltenango, Guatemala  three times 

for Mission and our church members took hundreds of bottled water to drink and we did not drink water from faucet 

Guatemala Missionary who was there for over 10 years advised us to drink bottled water only for Guatemala resident drinking water from the faucet won't get them sick but for the people from outside of Guatemala 

You can try this website

Never drink tap water in a foreign country unless it's in a decent hotel with a filtration system. The water may be safe for locals but your system may not be used to the same contaminants they are used to.

bottled water and ONLY bottled water that is sealed and you have opened yourself

A filter won't remove parasites