These are flat fees. The price we quote is the price you pay, and it covers plan check corrections. LA County plan checkers send comments, we respond, and that back-and-forth is part of the job, not a change order.
What Pushes the Price Up
Most Altadena rebuild lots fall into the flat-fee range above. Costs go beyond it when a site has complications that add real scope:
Steep lots with significant grade change across the building pad
Cross-lot drainage that requires an offsite drainage acceptance covenant with a neighbor
Sump pump design when gravity drainage will not work
Lots near a designated flood path or wash
If your lot is flat and drains to the street the way it did before the fire, you are the cheap case. That is most rebuild lots.
Where the Money Actually Goes
The drainage plan itself is a small line item compared to what it controls. A required sump pump system can add $30,000-$50,000 in construction costs. That is the number worth fighting, and it is why we calculate pre-fire and post-development flow rates on every project. If your post-development flow does not exceed pre-fire flow, the pump requirement can often be removed.
A $2,400 hydrology report that removes a $40,000 pump is the best money you will spend on this project. Here is how that analysis works.
What Is Not Included
Drainage and hydrology fees are separate from:
Architectural design fees
Geotechnical (soils) reports
Land surveys: your architect usually arranges this, and we need it to start
Grading plans, if your lot needs full civil design
Grading plans are quoted by scope because hillside lots vary too much for a flat fee. If your rebuild needs one, we quote it after seeing the survey.
Frequently Asked Questions
Drainage plans are typically $4,400 for an LA County residential rebuild. Hydrology reports run $2,400 as a separate document. These are flat fees, not hourly estimates, so the price does not change mid-project.
Steep lots, cross-lot drainage disputes with neighbors, sump pump design, and lots near a designated flood path all add scope. A flat lot with a simple sheet flow path is the cheapest case.
LA County does not require a hydrology report, but plan checkers use them to justify sump pump requirements. If post-development flow does not exceed pre-fire flow, the pump requirement can often be removed. A $2,400 report can save $30-50k in pump construction costs.
Yes. Drainage plans and hydrology reports are civil engineering documents billed separately from architectural and geotechnical fees. Ask your architect whether a survey is included in their scope, because we need one to start.
Once we have your survey and proposed site plan, a drainage plan typically takes 1-2 weeks. Rush timelines are possible if your building permit deadline is close.
Get a Fixed Quote
Send us your address and architect's contact. We will tell you what your lot needs and what it costs.