How to Read Engineering & Site Construction Plans as a Client

The grading plan shows how water moves across the site. It depicts existing and proposed elevations using contour lines — lines connecting points of equal elevation. The closer together the contour lines, the steeper the slope.

What to look for: How water drains off your lot and where it goes. Drainage should always flow away from your building pad toward a swale, inlet, or right-of-way — never toward an adjacent property or structure. Look for the building pad elevation — this tells you how high your finished floor will sit relative to the street and adjacent lots.

The water plan shows the location of water mains, service lines, fire hydrants, and meter locations. For a residential lot, the most important element is the water service stub-out — the point where the water main connects to your individual lot.

What to look for: Where your water meter will be located, what size service line is being provided, and whether fire hydrant spacing meets the required distance for your lot. If you're planning a large home, irrigation system, or fire suppression system, confirm the service line size and pressure supports your demand — in writing from the serving utility.

The sanitary sewer plan shows the collection system that carries wastewater away from your lot. Sanitary sewer is a gravity system — it flows downhill. The plan shows pipe sizes, manhole locations, invert elevations, and the direction of flow.

What to look for: The sanitary sewer lateral stub-out for your lot. Also look at invert elevations — these tell you how deep the sewer runs. If your basement or low-lying plumbing is below the sewer invert, you may need a lift station — a significant added cost that can add $50,000 or more to your project budget.

The drainage plan shows how stormwater is managed across the site — entirely separate from the sanitary sewer system. It includes storm drain inlets, pipes, detention ponds, and drainage swales. These two systems should never connect.

What to look for: Whether any drainage infrastructure crosses your building footprint. Drainage easements often follow swales and storm drain lines — anything within a drainage easement cannot have permanent structures placed over it. Check whether your lot has a drainage easement and exactly where it runs before you design your floor plan or any outdoor living structures.

The dry utility plan shows the layout of electric, gas, telephone, and cable infrastructure. Unlike water and sewer which are typically public utilities, dry utilities are often installed by private providers.

What to look for: Where the electric transformer serving your lot is located, where the gas meter stub-out will be, and whether conduit has been installed for fiber or cable service. If the transformer is on your lot, it comes with an easement that limits what you can build near it. Confirm lead times — electric service in particular can have 6–18 month lead times for new developments in North Texas.

The paving and sidewalk plan shows street widths, curb and gutter locations, sidewalk placement, and driveway approach locations.

What to look for: Where your driveway approach is shown — the curb cut that connects your driveway to the street. If the plan shows your driveway approach in a location that doesn't work with your floor plan or garage orientation, this must be addressed during the construction plan process — not after the curb is poured. Also check sidewalk easements carefully — they may affect your front setback calculations.