If i have well water on my property, how do you know it is ok to drink after an earthquake?

Water: You don't. That's why you have bottled water ready to go for emergencies.

Get it tested: By a reputable lab for trace elements that can be poisonous (like Sulfur or hydrocarbons - oil), or contaminants like pesticides or heavy metals (or even radioactivity) depending on what is buried nearby. Only a reputable lab can determine if your water is safe to drink; smell alone won't tell if there are smaller concentration of chemicals, some of which are odorless.

?: I don't think this is a medical issue. Ask a geologist. However,I can't think of a reason that it wouldn't be safe if it didn't look contaminated.

Call the county in: which you live. They will send out a specialist who will test the water and inspect pipes or anything else that might have been damaged in the earthquake and threaten the quality of your water. Private companies will also do this, but at a greater cost.

Well water: You can buy water testing kits at larger hardware stores such as home depot or lowe's. These kits test for basic contaminants that can be detrimental to your health. It would be wise to test from the well and from a faucet in the house.