Perc Tests and Health Department Approval in Putnam County, NY: A Guide for Land Buyers
- Published 20 octobar 2026
- Last reviewed 20 octobar 2026
- 7 min read
- Quick answer
In Putnam County, a vacant lot without public sewer is buildable only if the Putnam County Department of Health approves a septic system and a drilled well for it. That approval depends on witnessed deep test holes and percolation tests, reviewed against county standards that are stricter than the state minimum in several ways.
The detail that catches buyers most often: for new projects, the Department does not accept perc or deep-hole testing between July 15 and September 15, and it does not test on frozen or snow-covered ground. Build that into your contract dates.
Buyers often see Putnam lots listed “with approvals” or “with Board of Health approval”. That phrase can mean very different things — a current construction permit, a decades-old subdivision map, or simply a perc test someone ran years ago. This guide explains how soil testing and septic approval work in Putnam County, what makes a lot pass or fail, and what to verify before you sign. It is based on the Department’s published procedures for single-family residences (Bulletin ST-19); always confirm current requirements with the Department and a New York-licensed design professional.
On This Page
01
What "Board of Health Approval" Should Mean
02
How Soil Testing Works in Putnam County
03
The July 15 – September 15 Testing Window
04
Soil Standards That Decide Whether a Lot Passes
05
The Wel
06
Lots in the New York City Watershed
07
Older Lots and Neighbor Notice
08
From Approval to Certificate of Occupancy
09
Why Putnam Lots Fail
10
A Buyer’s Checklist
11
Frequently Asked Questions
What “Board of Health Approval” Should Mean
When a seller says a lot has approval, ask for the document itself and check four things:
What was approved. A construction permit for a specific septic system and well, or only a filed subdivision map with test data.
When. County construction permit approvals are valid for two years and must be renewed after that, and new percolation tests are required as a minimum on previously approved subdivision lots that are ten or more years old.
For how many bedrooms. The septic design is sized by bedroom count, and the county bases designs on a minimum of three bedrooms. Adding bedrooms later requires a new application.
For which house location. The approval is tied to the locations of the house, well, septic system, and driveway shown on the approved plan. Moving them requires the Department’s approval.
How Soil Testing Works in Putnam County
An engineering plan comes first. The Department will not schedule field testing without a plan prepared by a New York-licensed design professional, including a survey, two-foot contours, the proposed house, well, and septic locations, nearby wells and septic systems, and water features within 200 feet.
The town wetland board reviews first. . For projects needing witnessed testing, the plans go to the local town wetland board, which must confirm that test holes can be dug — or that a wetlands permit is needed first.
Deep test holes. At least four are required for each septic area — two in the primary area and two in the reserve area. For a normal absorption-trench system the holes are typically seven feet deep, and the Department inspects them.
Percolation tests. At least four, spread across the primary and reserve areas, run after a pre-soak that normally starts the day before. The slowest stabilized result governs the design.
Design and approval. The engineer designs the system to the results and submits for a construction permit. The approved construction permit then goes to the town building inspector with the house plans so the building permit can be issued.
The July 15 – September 15 Testing Window
Because dry-weather soil tests are frequently misleading, the Department does not consider new perc tests or deep-hole testing for new projects from July 15 through September 15. The exception is a lot that already has documented test data, such as a filed subdivision map or an approved construction permit. Testing also stops in inclement weather, on frozen ground, and under snow cover. In practice, that means a buyer who signs a contract in early summer with a short due-diligence period may not be able to complete testing before the contingency expires — negotiate the timing before you sign.
Soil Standards That Decide Whether a Lot Passes
| Requirement (Putnam County, single-family) | Why it matters to a buyer |
|---|---|
| At least 5 feet of usable soil between the bottom of the absorption system and ledge rock | Shallow rock is a common reason Putnam lots fail |
| At least 4 feet of unsaturated soil between the bottom of the system and groundwater | Seasonal high groundwater can rule out conventional systems |
| A 100 percent reserve area | You need room for two full septic fields, not one |
| Mounds, raised systems, shallow systems, and similar alternatives not allowed for new construction | Poor soils cannot simply be engineered around |
| Fill systems only with at least 3.5 feet of usable natural soil, and fill that settles for at least six months including a freeze-thaw cycle (or is mechanically compacted) | Fill adds time and cost to the schedule |
| Stricter treatment of very fast-draining soils inside the New York City watershed | Watershed lots have tighter design limits |
| Separation distances — for example, 100 feet between a well and a septic system (150 feet for seepage pits), with larger distances when the well is downhill | The lot must be big enough to fit the well, system, and reserve apart |
Where high groundwater is the problem, a curtain drain may help, but the Department requires groundwater monitoring during the normal high-water period (March 15 to June 30) to show it works — another seasonal constraint to plan around.
The Well
New homes must use a drilled well. The well must be pump-tested for at least six hours and yield at least five gallons per minute; wells that yield less require a 24-hour pump test and calculated water storage. A low-yield well does not always kill a project, but it adds cost and time.
Lots in the New York City Watershed
Much of Putnam County drains to New York City reservoirs. Under a delegation agreement, the county health department reviews septic systems in the watershed on behalf of the NYC Department of Environmental Protection, but the two agencies review jointly in certain cases — for example, systems within 500 feet of a reservoir, reservoir stem, or controlled lake; systems in the drainage basins of Boyds Corner, Croton Falls, or West Branch reservoirs; and, for lots in a realty subdivision, systems within 200 feet of a watercourse or a state-mapped wetland. DEP may also review stormwater plans and new impervious surfaces separately.
Older Lots and Neighbor Notice
For lots created before 1969, the Department will not review a construction permit application until the applicant proves that every adjoining owner was notified and given the latest site plan. Allow time for certified mail.
From Approval to Certificate of Occupancy
Once the septic system and well are built, the Department must issue a Certificate of Construction Compliance for the system before the town can issue a certificate of occupancy for the house. That step needs as-built plans from the design professional, a satisfactory water analysis, and the well completion report. Our guide explains what a certificate of occupancy is in New York and why it matters when you sell.
Why Putnam Lots Fail
Ledge rock too close to the surface to leave five feet of usable soil.
Seasonal high groundwater within four feet of the bottom of the proposed system.
Not enough room for both the primary and the full reserve septic area.
Required separations to wells, watercourses, wetlands, reservoirs, or neighbors’ systems cannot be met.
Slow percolation that makes the required absorption field too large for the lot.
Wetland restrictions that prevent test holes or construction in the only suitable area.
A Buyer’s Checklist
Ask for every health department document on the lot, with dates and bedroom counts.
Check whether the lot is in the New York City watershed and near a reservoir, stream, or mapped wetland.
Look at a soils map and walk the lot for rock outcrops and wet areas.
Confirm the lot can fit the house, well, primary and reserve septic areas, and required separations.
Set a due-diligence period that allows testing outside the July 15 – September 15 window.
udget for engineering, excavation for test holes, county fees, and possible fill or curtain drains. [VERIFY current county fee schedule]
For the broader list of zoning, access, and title checks, see what to check before buying vacant land in New York.
Frequently Asked Questions
Can I do a perc test in August in Putnam County?
Not for a new project. The Department does not accept new perc or deep-hole testing from July 15 through September 15, except on lots that already have documented test data.
Does an old approval still count?
Construction permits are valid for two years and must be renewed. On subdivision lots approved ten or more years ago, new perc tests are required as a minimum.
What happens if the lot fails?
Options can include testing another area of the lot, dewatering with a monitored curtain drain, or a fill system if enough natural soil exists. If none works, the lot is not buildable with a conventional septic system.
How long does county approval take?
It depends on the completeness of the engineering plan, the season, whether the town wetland board must review first, and whether the lot requires joint review with New York City DEP. Testing windows and joint review can add months, so start early. [VERIFY current review times with the Department]
Who performs the tests?
Your New York-licensed design professional arranges them and the Department witnesses or inspects them as its procedures require.
Do these rules apply in villages like Brewster or Cold Spring?
The county health department reviews septic and wells countywide where public sewer is not available; villages handle the building permit. Confirm sewer availability for the specific lot.
Buying land in Putnam?
Before you commit, our buildable lot evaluation in Putnam County checks septic feasibility, wells, wetlands, watershed setbacks, zoning, and access. See our pre-purchase land evaluation service for the full scope.