Which of the following is essential to check when installing plumbing fixtures?

When installing plumbing fixtures, checking local plumbing codes is essential because these codes establish the minimum requirements for safe and effective plumbing installations. Adhering to these codes ensures that the installation meets safety standards, protects public health, and confirms that the work complies with legal regulations. Local plumbing codes vary by jurisdiction, so it's crucial for a plumber to be familiar with the specific requirements relevant to their area.

While the quality of materials, design aesthetics, and manufacturer warranties are important considerations in the overall installation process, they do not have the same legal and safety ramifications as local plumbing codes. Failing to comply with these codes can lead to significant issues, including fines, the need for costly rework, and potential hazards that could arise from improperly installed plumbing systems. Thus, local plumbing codes are foundational to ensuring a successful and compliant installation of plumbing fixtures.