See Penalties for some of the mandatory penalties for a dwi conviction.
Besides mandatory fines, mandatory loss of license, and possible jail time, a DWI conviction can have other serious collateral consequences. These consequences include: a criminal record, to increased insurance, to a "drunk driving" program with possible follow-up for counseling, to a possible interlock device on your car (requires you to blow into the machine to operate the car), to possibly losing your job.
If you are convicted of DWI, you will now:
Have a criminal record. In New Hampshire, DWIs are either a misdemeanor, or felony.
Be required to carry SR-22 insurance. This will raise the cost of your insurance. Further, in NH, car insurance is normally optional. If you are convicted it is now mandatory.
Be required to complete a 20 hour drunk driving program, or a more intensive multiple offender program. If you are considered an at risk driver and get red flagged, you will be required to do aftercare before the DMV will re-instate your license.
Possibly need an interlock device. A DWI conviction has the possibility, which is mandatory in certain cases, of an interlock device. This is the machine you must have installed in your car and blow into before you can drive it. This machine has costs associated with.
What is an Interlock Device?
An Interlock device is an instrument you must blow into in order to start your car, and while driving, to determine that you do not have alcohol in your system. Most States set the cut-off failure at .020 or .025.
An Interlock is required if you have been found guilty of Aggravated DWI, or Subsequent offense DWI. In other cases, it is discretionary. In some cases, it may be volunteered in order to get the prosecutor to reduce the charge.
It will be required for 1-2 years. You need it on any vehicle you own or operate. The DMV will not give you your license back until you have it installed.
It works similar to a portable breath test. The newer models are more specific to alcohol, and supposedly have less false positives. However, if you have alcohol on your breath from things other than drinking, such as mouthwash, this will trigger the machine and you can be locked out. Failures are typically reported.
The cost to install it is around $100. The monthly cost to rent it is around $75 per month. Every so often you must have the vehicle inspected where the data is downloaded.
Be at risk of losing your job. Many employers will take action against you for a DWI conviction. The main categories of people who are at an increased risk are: teachers, police, fireman, other governmental employees, and anyone who drives for a living.
The only sure way to avoid these consequences is to not be found guilty of a DWI. Otherwise, the next best approach is to have an experienced lawyer negotiate with the State to work on minimizing the consequences of a conviction.