Yes, a modem can generally be placed in the utility closet. The utility closet is a common location for installing the modem because it is usually close to the entrance of the house and contains the necessary electrical and telecommunications connections.

However, there are a few important considerations when placing a modem in the utility closet:

1. Range: Ensure that the modem's signal range is sufficient to reach all areas of your home. If the utility closet is in a remote location or far from the main usage areas, it may be necessary to install additional wireless equipment, such as Wi-Fi boosters or access points, to ensure a good signal throughout the house.

2. Ventilation: Keep in mind that utility closets are usually small and enclosed, which can limit ventilation. Make sure there is adequate ventilation to prevent the modem from overheating. Good air circulation is important to keep the temperature low and to extend the modem's lifespan.

3. Interference: The utility closet may contain various electrical devices and cabling, such as power cables, switch panels, and electricity meters. These can cause electromagnetic interference that may affect the modem's signal. If possible, try to keep the modem at a safe distance from such sources of interference.

4. Accessibility: Ensure that the utility closet remains accessible for maintenance and possible adjustments to the modem or other equipment. It's important to be able to easily access the modem to troubleshoot any issues.

It is always a good idea to seek advice from a professional installer or provider to determine if the utility closet is a suitable location for your specific situation. They can assess the technical requirements and provide recommendations based on your needs.