Why This Matters Now
LA County reviews Altadena fire rebuild drainage plans differently after the Eaton Fire. When land clears, water moves differently. County plan check wants to see how your project handles post-fire runoff and keeps neighbors downhill safe.
We work through plan check every week. We know what LA County wants to see and how to present your Altadena drainage plans in a way that gets approved.
What We Do
- Altadena drainage plans
- Hydrology reports
- Pre-fire / Post-fire analysis
- Grading plans (when required)
- LID compliance (when required)
How It Works
- 1 Send us your survey and proposed site plan
- 2 We run the hydrology numbers comparing pre-fire and post-development conditions
- 3 You get an approved drainage plan ready for county submittal
Why Not Every Engineer Does This
LA County plan check for Altadena fire rebuilds has been changing weekly since the Eaton Fire. Most engineers are guessing. We've been doing this since 2011, so we're in the thick of it every week. We know what works and what doesn't.
We show your site drains the same way it did before the fire. That keeps you out of sump pump requirements and LID covenants. That's the goal for your Altadena drainage plan.
Frequently Asked Questions
A drainage plan handles water flow, minor grading, and keeping slopes at reasonable angles. A grading plan is full civil engineering required when a site has complex work outside the building footprint, such as large cuts or fills, retaining walls, or driveway work requiring tall walls. Most Altadena fire rebuilds only need a drainage plan.
Once we have your survey and proposed site plan, we typically turnaround a drainage plan in 1-2 weeks. If you need it faster for your building permit timeline, let us know. We work through LA County DPW plan check every week so we know what they want to see.
LA County does not require hydrology reports. But when they want to require a sump pump, we use a hydrology report to show your site drains the same way it did before the fire. We calculate pre-fire and post-development flow rates. If post-development Q does not exceed pre-fire Q, we can often get the pump requirement removed. Think of it as the tool we use to argue your way out of a sump pump on your Altadena fire rebuild.
LID (Low Impact Development) requirements are typically triggered when a project exceeds 50% impervious surface compared to pre-development conditions. We document this in the hydrology report. If your Altadena drainage plan stays under that threshold, LID requirements generally do not apply.
LA County checks if your post-development impervious surface increases by more than 50% compared to pre-fire conditions. Impervious surfaces include driveways, roofs, and concrete. If you stay under that threshold and your drainage plan maintains the pre-fire sheet flow pattern, LID requirements generally do not apply.
Drainage plans are typically $4,400 and hydrology reports are $2,400 when required. These are separate from your architect and geotechnical costs. The savings from avoiding a sump pump (which can run $30-50k in construction costs) far exceed the engineering fees for your Altadena fire rebuild.
For your specific Altadena project, talk to B+W Engineering.