Answered by LCD: As with many types of earthwork, depends on a lot of factors:

1) if it involves trapping or diverting a waterway officially classified as a stream - either perennial or emphemeral/intermittent, affecting or draining a wetlands, or otherwise affecting either wetlands or navigable waterways (including discharging directly into one of those), then you would need appropriate permits. May be covered by a "Nationwide" permit (which is generic simplified permit for small projects with minimal impact), or if directly impacting such areas might require a full section 401 or 404 permit, which are permits under federal law regarding Clean Water Act, and construction in navigable waterways and some tributary waters respectively. Those are major permits to obtain because they require Corps of Engineers, EPA, US Fish and Wildlife Service, and a multitude of other federal and state and local agency reviews - commonly costing tens of thousands of $ for an engineering or environmental firm to assemble the required reports or documentation and to maneuver them through the process, and very commonly in the hundreds of thousands to a million $ plus if significant impact or any endangered/ threatened species are involved.

Otherwise, your local Planning and Zoning office should also be able to guide you on permits needed regarding any work that exceeds the local limits on excavation without a permit, which can vary from around 5 or 10 cy of excavation/backfill on up to 100-1000cy or so depending on locale.

Many areas (as a fund-raising measure) also issue building permits with the permit cost based on job cost rather than just on whether it involves the life-safety related electrical/plumbing/HVAC/structural work, so if your job exceeds the local $ threshold then you will need a permit.

As far as "approval" permitting versus building permit fees based on job cost as a fund-raising measure, GENERALLY a small french drain within your yard which does not change the flow path of runoff as it enters or exits your yard, or foundation dewatering french drains with similar non-effect, do not require a permit.

Generally discharging any sort of such drainage from a french drain or sump pump into public sewers or drain ditches DOES require a permit from the receiving agency. So, a basement underdrain or french drain wet well discharge onto the ground by your house which soaks in on your property generally would not need a permit, whereas discharging into a sewer or street curb or roadside ditch would. Likewise, a french drain spreading the flow out on a downhill part of your yard so it does not create more of a concentrated flow across the property line than previously existed generally would not need a permit, but if it newly concentrates the flow at the property line (or at a different place) or dumps into a sewer or roadswide ditch it generally would.

If a major job you probably have a Civil Engineering firm doing the design - they can usually help with the permitting issues, or certainly know who can. For the normal small french right near the house to control basement infiltration issues, which discharges onto your yard so the runoff spreads out and soaks in, generally not. But check with planning and zoning and building permit departments to be sure.

A couple of other conditions where permits are commonly required, varying by local/state regs -

- if discharging within X feet (typically 25 or 50) of a well or leach field

- if passing over/within X feet (again commonly 25-50 feet) of a leach field

- if your area has a restricted use shallow water table requiring water use permits, french drains can be considered as equivalent to a well if they penetrate the water table, so need permitting

Of course, your contractor can give advice, but do not necessarily believe he knows all the rules - many do a LOT of things contrary to regulations, and as the property owner guess who is going to pay any fines. And don't count on being able to recover any fines from the contractor - not only are his pockets usually not that deep, but his insurance commonly specifically excludes environmental damage or claims.

Some of the 401 and 404 and threatened/endangered wildlife fines run up to at least as high as $10-16,000 PER DAY of infringement (commonly charged simultaneously from several federal or state agencies at one time under different laws for basically the same violation so can be up to about $50,000-100,000 per day), PLUS the cost of putting it back like it was, so not a good idea to chance it.

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