Downspouts and underground drain lines in Lewiston, ID

A downspout has two jobs: get the water off the roof, and get it away from the house. Most problems come from too few downspouts, downspouts that are too small, or downspouts that empty right against the foundation. Lewiston Rain Gutters adds, upsizes, and extends downspouts, and installs buried drain lines that carry the water out into the yard.

Trouble at the bottom of the downspout

Downspout problems show up on the ground. Walk around the house during a rain. Look at the base of each one.

A puddle or washed-out trench at the bottom of the downspout
A damp crawlspace or basement wall on the corner nearest a downspout
White, chalky crust on the foundation, which is mineral left behind as water soaks through concrete and dries
A splash block tipped over or sunk, so water now runs back toward the wall
An extension crushed or kicked aside by the mower or foot traffic
The gutter overflowing near the outlet in a hard rain, even when clean, which means the downspout is too small or there are too few
Water bubbling out where a downspout meets a buried pipe, a sign the underground line is clogged or crushed
Ice on a walk or driveway below a downspout that discharges across it in winter

A gutter and downspout running down the corner of a sided house under a blue sky — A gutter and downspout on a sided house.

How far water should go

A common guideline is to discharge roof water at least 4 to 6 feet from the foundation, onto ground that slopes away from the house. A splash block right at the wall doesn't meet that, and neither does an extension that ends in a low spot where water pools and soaks back in.

Downspout size and spacing

Residential downspouts are commonly 2x3 inch or 3x4 inch rectangular. The larger size carries much more water and passes leaves and twigs instead of clogging on them. A long run of gutter or a big roof section often needs a second downspout, or a larger one, to keep the gutter from overflowing at the outlet in a heavy rain. Adding an outlet means cutting into the gutter, so it's easiest to plan during a full gutter system install, but it can be added to existing gutters too.

Extensions or a buried drain line?

An above-ground extension is the simplest fix: a length of downspout or a flexible extension that carries water several feet out. It works well where it won't be in the way. Where it would cross a walkway, a driveway, or a lawn you mow every week, a buried line is the cleaner answer.

What a proper buried drain line looks like

Solid, smooth-wall pipe, not perforated pipe, so the water you collect isn't leaked back into the soil next to the foundation
A steady downhill slope the whole way, so the line drains empty instead of holding water that can freeze or collect sediment
A cleanout or debris filter where the downspout connects, so leaves can be removed before they get into the pipe
An outlet away from the house, either a pop-up emitter in the lawn that opens when water flows, or a daylight outlet where the yard slopes down

Where the water can and can't go

Roof water should end up on your own property, on ground that drains away from buildings. Pointing it toward a neighbor's yard or foundation causes problems for them and for you. Connecting to a street, curb, or storm system can be subject to city rules. If you want to discharge anywhere other than your own yard, check with the City of Lewiston first, or ask us and we'll tell you what we know before any digging starts. On sloped lots, such as those in Echo Hills or along Thain Road, the downhill side of the property is usually the right place for outlets.

Keeping it working

Clean the debris filter at the top of a buried line when you clean the gutters. If water starts backing up at the connection, run a hose into the line: if it doesn't come out at the emitter, the line needs to be cleared. Many buried-line clogs start with gutters that aren't cleaned often enough, which is where regular gutter cleaning pays for itself.

From hose test to backfill: installing a buried line

Map where the water goes now

Each downspout is checked, and water is run through the gutters to see where it lands and how the ground slopes around the house.
Plan the route and outlet

The route is laid out to keep a steady downhill slope to a spot where water can spread out safely, avoiding trees, walkways, and other buried lines where possible.
Utility locate

Idaho law requires a locate request through 811 before digging, so underground power, gas, water, and communication lines are marked first.
Trench and lay pipe

The trench is dug, the pipe is laid with consistent fall, and the downspout is connected through an adapter with a cleanout or filter.
Test and backfill

Water is run through the line to confirm it reaches the outlet. Then the trench is backfilled and the soil or sod is put back as closely as practical.

Extensions cost little; buried lines depend on distance and digging

Downspout extensions are a small job. Buried drain lines are priced mostly by how many downspouts are connected, how far the water has to travel, and what's in the way of the trench.

Number of downspouts being added, upsized, or connected
Upsizing: a larger downspout may need a larger outlet cut into the gutter
Length of buried line to a usable outlet
Digging conditions: rock, tree roots, slope, and crossing under concrete
Outlet type: pop-up emitter or daylight outlet
Restoring the yard: sod, landscaping, or pavers along the route
Height of the downspout on two-story walls

We give you a price after walking the property and seeing where the water needs to go.

Plan Lewiston drain line work before the spring rains

Lewiston's wettest stretch of the year is March through May, according to NOAA's 1991 to 2020 climate normals, with May the wettest month at about 1.7 inches. Spring rain arrives on top of whatever snowmelt is left, so this is when a downspout dumping at the foundation does the most damage.

That makes late summer and fall the right time to install buried lines. The ground is dry and easy to trench, there's time to settle the soil and regrow grass, and the system is in place before the water arrives.

The 811 step in Idaho

Under Idaho's underground damage prevention law, anyone digging, including homeowners, must request a utility locate at least 2 business days and no more than 10 business days before digging. You can call 811. Utilities then mark their lines on the ground with paint or flags. Build those days into the schedule if you're trying to finish before a wet spell, and don't dig your own trench for a downspout line without that call.

Source: Idaho Division of Occupational and Professional Licenses, Damage Prevention Board.

Downspout problems that need a call now

Call us at any hour if roof water is getting into the house or creating a hazard. We'll tell you how soon we can get there.

A downspout has been knocked off or torn loose in a storm and the runoff is pouring against the foundation
Water is coming into a basement or crawlspace near a downspout during rain
A clogged buried line is backing water up into a window well or under a slab
A downspout is discharging across a walkway or steps and freezing into a sheet of ice

Until we get there

Point the water away from the house with whatever you have: a spare length of downspout, a flexible extension, or even a tarp laid on the ground to channel it. Put ice melt or sand on any icy walkway below a downspout and keep people off it.

Call (208) 858-8002

If water is overflowing the gutter before it ever reaches the downspout, the fix is up top: a clog, a run that has lost its slope, or a corner leak. Those are covered on our gutter repair page. We handle downspout and drain line work across the city; see areas we serve.

Common questions about where roof water goes

How far from the house should a downspout drain?

A common guideline is at least 4 to 6 feet from the foundation, onto ground that slopes away from the house. Farther is better where the yard allows it.

Are underground downspout drains worth it?

They're worth it where an extension would be in the way, such as across a walkway, a driveway, or a lawn you mow, or where water needs to travel farther than an extension can take it. Installed with solid pipe, steady slope, and a cleanout, they work well for years.

What size downspout do I need?

Many homes use 2x3 inch downspouts, but 3x4 inch carries much more water and clogs less often. Long gutter runs, large roof sections, and houses with trees nearby are good candidates for the larger size or an extra downspout.

Can my downspout drain into the street or onto the sidewalk?

Discharging onto public property or connecting to a street or storm system may be regulated by the city. Check with the City of Lewiston before routing water off your property. Draining across a sidewalk also creates an ice hazard in winter.

Will a buried downspout line freeze in winter?

A line with a steady downhill slope drains empty after each rain, so there's little water left in it to freeze. Lines that sag or have low spots hold water and are the ones that freeze or clog. A pop-up emitter can freeze shut in a cold snap, so a backup above-ground outlet is useful on some houses.

Why is water backing up where my downspout goes into the ground?

The buried line is clogged, usually with leaves and sediment from the gutter, or the pipe has been crushed or has a low spot. Running a hose into the line shows whether water reaches the outlet. If it doesn't, the line needs to be cleared or a section replaced.

Get roof water away from your foundation

Call Lewiston Rain Gutters at (208) 858-8002. Tell us where the water is pooling or coming in, and whether you're thinking about extensions or buried lines. We'll look at the property, explain where the water should go, and give you a price.