North Shore, the middle and the South ShoreGround or house, settled first(315) 640-3590
$100 off your first job, credited by us. Terms apply.

Nassau County

Mold Removal in Syosset, NY, With the Water Table 165 Feet Down

Mold in a Syosset lower level almost always traces back to the house or the weather, and an assessment finds which one so you are not paying to keep out groundwater that cannot reach you. A USGS well inside Syosset, at about 227 feet above sea level, read the water table close to 165 feet below the surface, and the Syosset weather station averages 47.73 inches of precipitation a year, more than Mineola.

1955is the median year built across Nassau County's 479,044 homes in Census estimates for 2020 to 2024
0.37 ftbelow the surface was the water table at a USGS well on Manhasset Neck in spring 2016
165.27 ftbelow the surface was the water table at a second Manhasset Neck well about 1.3 miles away
Get In Touch

Request a quote in Syosset

Tell us the town, the lowest level of the house and where the damp is showing. In Nassau that is usually enough to say whether the water is coming up from the ground or out of the house, and which licensed trade the job needs.

Would you rather talk it through? Call (315) 640-3590.

$100credit

$100 off your first job

Credited by us on your first booked job.

  • One credit per customer per property, on your first booked job.
  • Valid through December 31, 2026.
Start Your Quote

Mention this offer when you book. Full terms.

Six quick questions about the house and where the damp is showing, then your details. It takes about a minute.

Question 1What are you dealing with?
Question 2Which part of the county is the house in?

How far down the water sits under a Nassau house changes a great deal from the South Shore to the North Shore hills. Near the bays and harbors it can be close to the surface. Under much of the middle of the island and the hills it is far below the floor, so damp there usually comes from the house itself. The town is enough, and not sure is a fine answer.

Question 3What is the lowest level of the house?

A house built on a concrete slab, a house with a basement and a house over a crawl space get wet in different ways, and the fix is different for each. Many homes in this county were built on slabs with no basement at all.

Question 4Where is it showing up?

Where the damp appears is the first clue to which way the water came. Damp that starts low and spreads up points one way, and damp around a fixture, a window or a ceiling points another.

Question 5How long has this been going on?

Something that got wet in the last day or two can often still be dried. Something that has stayed damp for weeks usually cannot, and the job changes.

Question 6What would you like to happen next?

In New York the company that assesses mold and the company that removes it cannot be the same company on one job, so it helps to know where you want to start.

The house, the damp, and how to reach you

Who should we ask for?

How can we reach you?

We call to confirm the details before anyone is sent out.

Where is the property?

The contractor match is by property, not by person, so the street line matters.

Anything else we should know?

Your $100 credit is attached to this request. Mention this offer when you book. See terms.

Your details are used only to respond to this request and arrange the service.

Local Detail

Syosset's well depth and rainfall on record

Basement boiler with copper lines and a small drip stain from a slow leak

USGS well N 1228, inside Syosset at about 227 feet above sea level, measured the water table between 164.83 and 164.88 feet below the surface in three readings from March to May 2016.

Source: U.S. Geological Survey, Water Data for the Nation, groundwater field measurements, accessed 2026-09-23

NOAA's 1991 to 2020 normals for the Syosset station, at about 265 feet above sea level, give 47.73 inches of precipitation a year, more than Mineola's 45.33; the station publishes no temperature or snowfall normals.

Source: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020, annual and seasonal, station USC00308577 Syosset, accessed 2026-09-23

Census estimates for 2020 to 2024 count 6,164 housing units in Syosset with 54.9 percent built in the 1950s, a median year built of 1958, 91.9 percent single detached houses and 40.0 percent of homes heating with fuel oil.

Source: US Census Bureau, American Community Survey 2020-2024 5-year estimates, Syosset CDP, tables B25034, B25035, B25003, B25024 and B25040, accessed 2026-09-23

Next Step

When does the Syosset basement get wet?

After heavy rain, all summer, or all the time? Tell us, because in Syosset the timing points straight at the gutter, the air or the plumbing.

Planning

Finding the real source in a Syosset basement

Syosset is a hamlet in the Town of Oyster Bay, so permits for tearing out and rebuilding a finished basement go through the town. Most of the housing comes from a single decade, with 54.9 percent built in the 1950s, which means many basements have been finished, refinished and carpeted over the years. With groundwater this far down, water in a Syosset basement came from above or from inside: a gutter emptying at the foundation, ground sloping toward the house, a window well filling in a downpour, a slow supply leak, or summer condensation on cold walls and pipes. Each of those has its own trade, and none of them is a sump pump. The assessor's written plan names the source, and fixing that source is what stops the mold returning after the cleanup.

North Shore shingle colonial on a wooded hillside with a climbing driveway
A booking service, not the contractorWe arrange the job and a separately licensed New York firm carries it out, sets its own price and signs its own agreement with you.
The firm that assesses never removesState law keeps the company that writes the mold plan apart from the company that carries it out, and bars one owner from holding a stake in both on your property.
Every trade licensed and insuredEvery firm we book holds the New York license its part of the work calls for, and you can look any mold license up on the state's own open register.
Availability

What we arrange for Syosset homes

Mold Inspection and Assessment

Find out whether the water behind the mold is coming up from the ground or out of the house itself, and get the scope in writing before anyone quotes for removal.

Mold Inspection in Syosset →

Mold Remediation and Removal

Have the growth taken out by a licensed remediation firm working to the independent assessor's written plan, with the water that fed it repaired first.

Mold Remediation in Syosset →

Water Damage Drying and Restoration

Get the water out and the structure dried before mold starts, including the slab, the flooring and the finished basement walls where water hides.

Water Damage Drying in Syosset →
Next Step

Tell us what the Syosset basement looks like

We read it and write back. If a regraded bed or a longer downspout is the whole answer, we will say that rather than send anyone.

Start Your QuoteCall (315) 640-3590
Start Your Quote