We perform an assessment of impermeability of pipes themselves (vitrified clay, concrete) including accurate measurement of water loss under specified conditions (pressure, exposure time). The determination of impermeability of the joint at a pair of pipes can be performed on a special test bench – again under specified conditions (pressure, exposure time, pipes deflection etc.) Determination is performed according to ČSN (e.g. ČSN EN 295-3) and DIN.