Breath Testing

In Waterbury, if a police officer thinks that someone is driving under the influence of alcohol, they may ask that person to submit to a breath test, also known as a breathalyzer test. Failure to take the test or failing the test is a violation of implied consent laws in Connecticut. On this page, you can learn more about implied consent and the pros and cons of taking a breath test.


In Waterbury, police officers will often use breath testing machines called breathalyzers to test the blood alcohol concentration (BAC) of a person after they have been arrested for DUI. The way these machines work is that the subject will take a breath and exhale into a small mouthpiece, where the air travels into the device and passes through light.

Henry’s Law

The science that the breathalyzer is based upon is called “Henry’s Law,” which is the “mass of gas that dissolves in a definite volume of liquid which is directly proportional to the pressure of the gas provided that the gas doesn’t react with the solvent.” In other words, if a gas and a liquid are confined together in a container, the concentration of gas to air above the liquid is the same to the gas dissolved in that liquid.

One way to think of this is when blood containing alcohol is in a closed container. The alcohol will evaporate until the concentration in the air above the blood is equal to the concentration in the liquid. Henry’s constant is the ratio given to the blood in the human body to the air. This ratio is 2100:1. The average concentration of alcohol in a person’s blood is around 2100 times greater than the concentration in the air with it.

Call us today to schedule a free consultation with my team. Hope will not fix your Connecticut DUI charge. Contacting us can!

Call Today

Factors that Could Make Breath Testing Unreliable

This is a problem because there is no “normal” amount of blood to air equilibrium that can be used as a constant for every person. This is because every person has a different size, weight, and physical makeup than the next person. Because of this problem, scientists estimate that there is at least a 0.03% error in each breathalyzer due to the normal ratio being used as a constant in the device. This can make a big difference when attempting to charge someone with DUI.

A person’s body temperature can also greatly impact the results of a breathalyzer because blood alcohol concentration in the body can increase in percentage when the body temperature increases or decreases even slightly. Taking a large dose of aspirin can even affect the body temperature enough to alter the breathalyzer results. Other factors like diabetes, sickness, or medication can possibly be defenses to breathalyzer results.

There are other factors that can seriously alter the accuracy of breathalyzer results. The most common defense is poor maintenance or improper calibration of the device. Improper calibration occurs when the calibration is not done correctly. To ensure accuracy, law enforcement have guidelines to follow.

The breath test must be properly calibrated and maintained at consistent, set intervals. The person administering the test must be trained and certified to ensure that the test is done correctly. The officer must also make sure that the subject has not burped, vomited, eaten, or smoked just before taking the test. Lastly, the breathalyzer test has to capture two reliable results in measurements that are within .02 of each other.

Connecticut has an implied consent law. It means that any person that gets behind the wheel implicitly consents to taking a breathalyzer test to test their blood alcohol level. Despite this law, citizens can still decline to take the test and face consequences such as automatic license suspension, rather than face possibly greater consequences of having breath test results admitted during a criminal court case.

A good DUI lawyer will be able to analyze a DUI case where there are breathalyzer results or a refusal and figure out what the best course of action is. If you have been arrested for a DUI in Waterbury, call Lady DUI to find out more.

Get A Copy To Your Inbox

Get your free copy of Teresa's eBook on surviving a Connecticut DUI. Delivered right to your inbox.

Free Case Evaluation

Give us a little information about your situation and schedule your free case evaluation. We can have a consultation over the phone, via Skype or Zoom or we can meet at one of our convenient offices across Connecticut.