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Do This, Not That - Yard Drainage in Sonoma County, CA

Updated: Feb 26, 2023

"I just installed a drain and it doesn't work. Can you fix this?"



That's a common call for me. Sadly, this botched job has often exhausted a homeowner's budget and the correct solution was just barely out of reach the first time.


Remember - The difference between mediocrity and excellence is 10%. Most projects are 90% of the way to being perfect - they simply omit a simple step or component.


1) Don't lay pipes flat!


You bought the expensive pipes, used clean rocks, dug for days and fit everything up just right - or even worse, hired a "pro" for tens of thousands - and now the water just stays in the pipe. All bad!


The minimum slope for drain pipes UNDER 4 inches is 1/2 inches per 10 feet. For pipes greater than 4 inches, a 1/4 inch per 10 foot drop can work, since there's less friction inside the pipe. Even if the improperly sloped pipe DOES eventually drain, it won't drain fast. Standing water can breed mosquitos, and smell terrible when mold and moss propagates in the pipes.


DO - Consider a dry well


Dry wells function similarly to a septic - they disperse unwanted water under the earth, where it filters, percolates, and returns to the groundwater table as squeaky-clean potable water. A dry well can be as simple as a small hole filled with gravel, or as complex as a multi-chambered design made of giant precast chambers!


Pictured here is an NDS Flo-Well. It is a small chamber typically used for downspout extensions. A flo-well per downspout is typically sufficient for California downspouts, but of course, it is best practice to perform soil infiltration tests and add up the square footage of the area to be diverted into the well before breaking ground. Dry wells may not work as intended in certain areas of the county with extremely clay based soils or high water tables, such as the "L" blocks of Cotati, or the Roberts Road/Adobe Road area of Penngrove.


Dry wells fix two problems - they give water a "low spot" to drain to, for oddly sloped or limited slope locations. They also "re-charge) underground aquifers - which sorely need the extra help. Imagine if everyone had a proper dry well, and no water spilled into the streets. Flooding, property damage, and public safety would be greatly enhanced.


Don't - Use Black Pipes


There are two black pipes I see used as drain pipes far too often. The first one is known as "ADS" and looks like this:


The other is ABS, and looks like this.


ADS is incredibly common and incredibly sub-optimal. It's not particularly crush resistant, and has a habit of caving in when exposed to any level of ground compaction or settlement. The flexible nature of the pipe makes ADS a dream to install, but if it isn't bedded perfectly, it tends to get deformed and trap water in a low spot. Speaking of trapping water, the inner walls of ADS are ribbed, and slow water flow to a crawl. You can have a run of ADS sized and sloped perfectly for the application, only to learn that water flows through it like molasses and the system does not work in a sudden high-flow situation spurred by a storm.


The other pipe is ABS, and while it flows excellent and holds up to years of storms and compaction, it's brittle compared to PVC and can get confused for an old-school sewage system when another contractor digs it up. Plus, it's not a great value. If you're price shopping, triple-wall drain pipe is for you. If you're building it bombproof, PVC is the way. ABS is an odd choice, far outshined by its modern peers.


DO - consider rock options



Just because 3/4 drain rock is the most popular doesn't make it the best. 3/4 drain rock is awesome stuff! It doesn't settle, allows water to flow freely, and is seemingly available everywhere. If it were any more popular, you could walk in and buy it in Target.


1in and 1.5in drain rock is the bigger brother to 3/4 drain rock. The shape and texture is the same - but bigger rocks allow bigger pores, allowing more water to travel through faster in a french drain or dry well. On french drain to dry well installs, I like to order 3/4 drain rock to bed the pipes in it. The small texture allows ease of use and helps me & my employees bed the pipes more accurately. But when I fill in the well, it's 1.5in drain rock I choose, since the more pore space I allow myself, the more water can be retained and passed through. It's little tricks like these that seperate the "good contractors" from the great ones.


Also, don't overlook river rock or pea gravel. In Sonoma County, it's over double the price, but smooth, round rocks have benefits. If you're building a french drain or dry well with an "open top" (the rocks are not hidden underground) smooth round rocks can be more pleasing to the eye. Many contractors swear up and down it drains much faster, and is undoubtedly easier to manage with shovels and level with rakes, since it rolls over itself like ball bearings instead of locking together in a mass. But be warned - this easy handling quality may not compact as nicely as rougher crushed rocks. I personally stay away from the round rocks if people or vehicles will ever travel over the area with any level of frequency.


Don't - Tie everything into a french drain pipe



Okay, mask off. I did this. Twice. It wasn't an effort to save time or materials, it was simple inexperience as a young contractor doing all I could with what I knew. To this day, the clients never contacted me or complained about it - heck, one of them called me over-the-moon about how well it handled the recent storms, but I sometimes lay in bed and curse the days when I tied downspouts into a foundation french drain.


A downspout extension, channel drain, or drain tile is designed to quickly catch surface runoff and carry it somewhere else.


A french drain is designed to slowly pull surface water and soil water from a typically low or oversaturated area.


The two systems work off different philosophies of use and simply aren't compatible in my educated opinion. If typical downspouts and drain tiles are quickly diverting water into a typical french drain system that captures a completely different type of water and needs to work slowly, the french drain will spend all its life being overtaxed by rapid water ingress and won't work to its fullest potential.


Don't get me wrong - the pipes can be buried in the same trench and eventually tie in to the same creek, gully, gutter, tank, or dry well, but the solid wall downspout or drain tile pipes shouldn't be feeding directly into perforated french drain pipes. The former simply needs to be piped directly to the destination and the french drain should be left alone to acquire and send away water at its own pace. It's simple, but maddeningly difficult to explain on paper. I would love to make a youtube video on this, but fortunately, a skilled professional already has. He's a North Carolina guy, but suprisingly, the soils in his area are very similar to ours. Click this link:



DO: Figure out your "Why's" first!



WHY do i need a drain? WHY is water here a problem? WHY do I want THIS type of drain, and not another?


Sometimes, it may not be a drain that fixes your problem.


Oftentimes, a job well done could be a simple re-grade, or an above ground ditch, swale, or culvert. This is incredily common on rural sloped properties where water is OK on one part of the property, but it ends up on another.


Be a detective. Figure out where the water comes from. If your municipality won't fix a clogged culvert and the water puddled up in your place instead, file a complaint. If your neighbor concreted his whole backyard and now you're his/her floodplain, maybe it's time to raise your voice and have a hard conversation.


Winglewich Landscape Contracting has played detective season after season for Sonoma County residents struggling with stormwater problems. We promise to listen carefully, use all our senses of observation, and offer many options and competitive rates on your journey to a drier backyard. From a consultation, to a repair, to a new build, call 707-755-0612.


If I don't answer right away, I'm probably knee deep in an excavation trying to get my pipes to slope just right.


- Sam Winglewich.



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