A hydraulic plumber's friend has a cylindrical body, a lid, a compression assembly, a tapered end cap and a nozzle assembly. The cylindrical body has an open bottom and holds water to be injected into a clogged pipe. The compression assembly has a drive shaft and a piston mounted slidably in the cylindrical body. The tapered end cap is mounted on the open bottom of the cylindrical body and has a transverse partition, a tapered body and a spout. The nozzle assembly has a valve having a cylindrical disk mounted slidably in the spout and having a closed top, an open bottom, a cylindrical sidewall and multiple charging holes, a valve stem and a spring. When the charging holes are uncovered, water flows. The nozzle is mounted on the cylindrical disk and seals and directs water into an opening in a clogged pipe.