Yes. Plumbing work is generally safe for people with ICDs. The tools and materials used in most plumbing tasks do not generate electromagnetic fields that would affect your device.
If your work involves power tools with electric motors, apply the standard precaution of keeping the motor at least 15cm (6 inches) from your device. If you work near large pump motors or industrial electrical systems, the same principles as for other industrial environments apply — discuss your specific work environment with your cardiologist or device clinic if you have concerns.