Yes, and buried downspouts are often the cheapest drainage fix on a property. The rule that matters is not how deep the pipe goes, it is where it ends. It has to fall the whole way and come out somewhere the water is allowed to go: daylight lower on your own property, a dry well, or the street or storm system where your town permits it. Never the sanitary sewer, which is prohibited in New Jersey.
A roof is the biggest single source of water on most house lots. Every inch of rain on it lands in a few gutters and comes down in a few spots, usually right beside the foundation. Moving that water away is the first thing to try before anybody talks about a French drain, and it frequently is the whole fix. We said as much in French drain, catch basin or dry well, where downspout work sits at the bottom of the cost ladder for a reason.
Where a buried downspout is allowed to go
- Daylight, lower on your own property. The best and cheapest answer. The pipe runs downhill and simply comes out of the ground somewhere the water can spread and soak in.
- A dry well. When there is no lower ground to daylight to, the water goes into a structure that lets it soak away. This is the expensive answer, and it is only as good as the soil around it.
- The street or storm system, if the town allows it. This is the town's system and the town's call, so it is a question for the municipal engineer or public works, not an assumption.
What is not an answer: the neighbor's yard, a stream or wetland, or the sanitary sewer. New Jersey's sewer design rules require roof water to be kept out of sanitary sewers, and the state's capacity assurance rules name disconnecting roof leaders from sanitary lines as a required strategy. A roof tied into the sewer is how a treatment plant gets overwhelmed in a storm, and it is how basements on the same street take on sewage.
Watch the sidewalk too. Some towns around here, Franklin Township in Somerset County among them, treat a discharge that causes icing, standing water or erosion on a street or sidewalk as a problem in its own right, which is how a pipe that has run to the curb for twenty years suddenly gets a notice one winter. Our sump pump discharge page walks through the same rules, because a sump line and a downspout line are governed the same way.
How to bury one so it keeps working
- Solid pipe, not perforated, for a line whose job is to carry roof water away. Perforated pipe leaks the water back out along the way, often right next to the foundation you were trying to protect.
- Fall the whole way. A buried downspout that sags in the middle holds water in the low spot. That water freezes in January, silts up in summer, and backs the gutter up in a storm.
- A way in to clean it. Roof water carries grit and leaves. A cleanout or a removable fitting at the downspout end saves digging it up later.
- A real outlet. A pop-up emitter or an open end at a lower point, somewhere the water can spread out without eroding a gully.
There is no single New Jersey depth for a downspout line the way there is for a water service. The pipe needs enough cover to be protected from mowers and foot traffic, and enough slope to drain empty between storms. A pipe that drains empty is a pipe that does not freeze.
Do I need a permit to bury downspouts?
For a simple line on your own property that daylights on your own property, usually not from the state. A typical downspout trench disturbs a small fraction of the 5,000 square feet that brings in a soil erosion plan. A connection to the street, a curb or a municipal storm system is different, and towns commonly want to approve that before it exists. Call your construction or engineering office first.
A note for Sussex and Warren
In the limestone valleys, concentrated water is one of the things that opens sinkholes, and a downspout discharging in one spot is a textbook example. If you are on karst ground, spreading the water out matters more than getting it far away. We wrote about that in sinkholes in Sussex County.
When it is more than a downspout
If the yard stays soft after the roof water is handled, the water is coming from somewhere else: groundwater, runoff from a neighbor's slope, or a leaking pipe. That is a diagnosis on site, and it is what our grading and drainage work is for.
Common questions
Can you bury downspouts? Yes. Use solid pipe with continuous fall and a proper outlet: daylight lower on your own property, a dry well, or the street or storm system if your town allows it.
Can downspouts go into the sewer in New Jersey? No. New Jersey requires roof water to be kept out of sanitary sewers, and the state's capacity assurance rules name disconnecting roof leaders from sanitary lines as a required strategy.
Do I need a permit to bury downspouts in NJ? Usually not for a line that stays on your property. A connection to the street or a municipal storm system typically needs the town's approval first.
Do buried downspouts freeze? They can if the pipe sags and holds water in a low spot. A line with continuous fall drains empty between storms, and a line that drains empty does not freeze.
Should a buried downspout use perforated pipe? Not for a line meant to carry roof water away. Perforated pipe lets the water back out along the run, often right next to the foundation.
Still not sure how this applies to your property? That is what a free on-site estimate is for. Call 862-268-2510 or tell us what is going on, and we will give you a straight answer, including when the answer is that you do not need us.