According to the design criteria, how close can a manhole be installed to an existing waterline?

The design criteria for installing a manhole in relation to an existing waterline emphasizes safety and the prevention of contamination. The guideline that allows a manhole to be installed within 9 feet of a waterline, provided it is completely watertight and has been tested, is grounded in best practices for ensuring that sewage and wastewater systems do not compromise potable water supplies.

This specific distance reflects an understanding of potential risks associated with leaks or overflow from the sewer system. By requiring both watertight integrity and testing, it ensures that even in close proximity to drinking water infrastructure, the materials used, as well as their installation, prevent any possible cross-contamination. This protective measure is crucial in maintaining public health and safeguarding water quality in the surrounding areas.

Overall, the specified distance and the conditions for watertightness highlight the importance of engineering standards that prioritize both accessibility for maintenance and protection against environmental hazards.