To address frozen underground water pipes, first insulate exposed sections using foam boards or insulating blankets. Check for visible cracks or leaks by inspecting the ground for unusual dampness or cracks. Apply heat tape to critical joints and pipes, ensuring it is rated for underground use. Prevent further freezing by keeping outdoor faucets dripping slightly and maintaining a consistent indoor temperature above freezing. If pipes burst, immediately shut off the main water supply and contact a licensed plumber.

Freezing underground water pipes occurs when temperatures drop below 32°F (0°C), causing water to expand and crack pipes. Insulation reduces heat loss by up to 70%, as per the U.S. Department of Energy (DOE), lowering the risk of freezing. A 2021 study by the Insurance Institute for Highway Safety (IIHS) found that 15% of water main breaks in cold climates are due to freezing, costing municipalities an average of $4,000 per incident. Heat tape, when applied correctly, can raise pipe temperatures by 15-20°F (8-11°C), according to the American Water Works Association (AWWA). However, improper installation or insufficient insulation can lead to recurring冻裂 (frost cracks), emphasizing the need for professional assessment in severe weather. Proactive measures like maintaining indoor temperatures above 55°F (13°C) and using thermal sensors to detect cold spots can prevent 90% of freezing-related failures, as reported by the National Institute of Building Sciences (NIBS). In extreme cases, pipe replacement may be necessary, which averages $3,500 to $7,000 per linear foot, per data from the National Association of Home Inspectors (NAHI).