Studies were conducted to evaluate the impact of stagnation period on the metal dissolution from plumbing materials including lead, copper and brass. Experimental data showed that metal levels increased exponentially with time, with the sharpest increase occurring over the first 20–24 h. Metal levels may continue to increase following well beyond 24 h of stagnation. Copper levels increased until dissolved oxygen fell below 1 mg l−1 after which copper levels fell. Results showed that stagnation behaviour is complex in nature, difficult to predict and dependent on water chemistry. Experimental data fit well to a radial diffusion model when a diffusion barrier term is considered.