Dry Well Installation in Lancaster, PA

A dry well is a buried pit that collects water from a drain and lets it soak slowly into the ground. We build them for Lancaster homeowners whose French drain, downspouts or sump pump discharge have no open slope and no storm sewer to reach.

What a dry well does at the end of a drain

A drain only moves water. It has to end somewhere. On a flat lot, or one hemmed in by neighbours and a street with no storm connection, there is no slope to carry a pipe out to open ground. A dry well fixes that. The pipe runs into a buried pit, the pit fills during a storm, and the water seeps out through the bottom and sides into the surrounding soil over the following hours.

This page is about the pit itself. The trench and perforated pipe that feed it are covered under French Drain Installation. A dry well can also take roof water, a sump pump discharge line or a low-spot drain, so we sometimes build one on a job that has no trench at all.

Types of dry well

The right build depends on how much water arrives, how much room you have and whether a machine can reach the spot.

Gravel-filled pit

This is an excavated hole lined with filter fabric and filled with washed, clean stone. Water enters through a solid pipe near the top and moves through the gaps between the stones. It is the simplest build and suits a single downspout or a modest drain line.

Precast concrete rings

Perforated concrete cylinders are stacked in a round hole, capped with a lid and surrounded by stone. The inside stays open, so the ring holds more water than a stone pit of the same size, and a cover lets you look in later. Setting the rings takes machine access.

Plastic chamber systems

Molded arched or box chambers wrapped in fabric store a lot of water for the size of the hole. They are light enough to carry by hand, which helps in a rear yard reached only through a gate or a narrow side passage.

Sizing a dry well and testing the soil

Size comes down to three things: how much roof and paved area drains to the pit, how fast the soil takes in water, and how deep the seasonal water table and rock sit. Before we dig the pit, we dig a test hole, fill it with water and watch how quickly it drops. Sandy or loamy soil empties fast. Heavy clay can stay full for days. A pit that cannot empty between storms is just a buried tank, and it backs up into the pipe.

Placement matters as much as size. We check these before marking the spot:

• Distance from the foundation, so the soaked ground is not sitting against your basement wall
• Distance from a septic tank or field, a drinking-water well and the property line
• Buried gas, water, electric and sewer lines, which are marked before any digging
• Slope of the yard, so overflow has a safe path if the pit ever fills completely

How a dry well installation goes, step by step

Most residential dry wells take a day or two once the layout is settled.

Marking and the test hole

We confirm utility marks, pick the location and run the soil test. If the hole does not drain, we talk through other outlets before any real digging starts.

Digging and lining the pit

The hole is dug below the inlet pipe and into soil that drinks water. The walls are lined with non-woven filter fabric so silt from the surrounding ground cannot wash into the stone and clog it.

Setting stone, rings or chambers

A bed of clean stone goes in first. Then comes the stone fill, the concrete rings or the plastic chambers, depending on the design. Washed stone matters here: stone with dust on it fills its own gaps.

Connecting the inlet and backfilling

The inlet pipe is set at a steady fall toward the pit. We wrap the top of the stone in fabric, add a layer of soil and restore the lawn. A cleanout or cover is left accessible if the design has one.

Dry wells in Lancaster soils and weather

Lancaster sits in the Piedmont region, slightly north of the Conestoga River. The city averages 42 inches of precipitation a year, and September is the wettest month, so a dry well here has to cope with repeated heavy storms, not just a slow annual total. Soil in the Piedmont changes from lot to lot, which is why we test each location instead of assuming the neighbour's pit will work for you.

The city was settled in the 1720s, and older neighbourhoods such as the Historic East Side and the West End were built long before anyone planned for roof water. In those areas, a small lot may leave little room for a pit. A foundation that already struggles with moisture may also need a foundation drain before a dry well makes sense.

When a dry well is the wrong outlet

A dry well is not the answer everywhere. Dense clay, a high seasonal water table or shallow rock can leave the pit with nowhere for water to go. In those cases we look at other discharge points instead.

If your lot has a lower corner or a ditch where water can leave safely, a curtain drain can intercept water uphill and carry it to open ground without a pit at all. We would rather say that up front than build a pit that fails the first wet September.

Keeping a dry well working

Silt and leaves are what shorten a dry well's life. Keep gutters clean, and fit a leaf screen or filter at the downspout if trees overhang the roof. If the pit has a cover, lift it once a year and look for standing water or a layer of sediment.

Signs of trouble are water pooling over the pit, gutters that back up in heavy rain, or a drain that gurgles and runs slow. Most of the time the cause is a clogged inlet or silted stone, and catching it early keeps the repair small.