Well water in Alstead, New Hampshire
In Alstead, none of 31 private wells tested between 2006 and 2020 had nitrate above the New Hampshire guidance level (10 mg/L), according to NH DHHS.
31 private wells tested 2006 to 2020 in state summaries. Data refreshed .
Separately, a USGS and NHDES statistical model puts the chance that a bedrock well in Alstead exceeds 5 ug/L of arsenic at 10% (as low as 1% in parts of town), based on geology rather than tests.
What homeowner tests found
NH DHHS WISDOM private well summaries: private wells tested and reported to the state, 2006 to 2020. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Sodium | 22 | 23% | 8.5 | 68.6 | 214 | 20 mg/L | |
| Lead (stagnant) | 21 | 19% | 4.4 | 42.9 | 51.1 | 15 ug/L | |
| Manganese | 22 | 18% | 0 | 600 | 2,400 | 300 ug/L | |
| Iron | 22 | 18% | 0 | 2,000 | 5,500 | 300 ug/L | |
| Copper (stagnant) | 21 | 10% | 0.1 | 2.5 | 3.2 | 1.3 mg/L | |
| Arsenic | 23 | 9% | 0.7 | 4.8 | 5.3 | 5 ug/L | |
| Chloride | 31 | 6% | 13 | 225 | 350 | 250 mg/L | |
| Uranium | 23 | 4% | 0.7 | 3.7 | 81 | 30 ug/L | |
| Nitrate | 31 | 0% | 0.1 | 1.8 | 3.7 | 10 mg/L | |
| Nitrite | 31 | 0% | 0 | 0 | 0 | 1 mg/L | |
| Fluoride | 29 | 0% | 0.2 | 2.1 | 2.6 | 4 mg/L |
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What this means
Among homeowners in Alstead who sent a sample to the state lab, the health-based limits most often exceeded were lead (19% of 21 wells), copper (10% of 21 wells), and arsenic (9% of 23 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
Sodium, manganese, and iron exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Alstead
- Volatile organic compounds (VOCs)1 leaking underground storage tank site on record locally.
- PFAS2 unlined landfills on record locally.
- Metals panel1 hazardous waste site on record locally.
- Sodium23% of 22 local wells tested were above the New Hampshire guidance level.
- Lead19% of 21 local wells tested were above the New Hampshire guidance level.
- Manganese18% of 22 local wells tested were above the New Hampshire guidance level.
- Iron18% of 22 local wells tested were above the New Hampshire guidance level.
- Copper10% of 21 local wells tested were above the New Hampshire guidance level.
- Arsenic9% of 23 local wells tested were above the New Hampshire guidance level.
- Chloride6% of 31 local wells tested were above the New Hampshire guidance level.
- Uranium4% of 23 local wells tested were above the New Hampshire guidance level.
Wells in Alstead
217 domestic wells in Alstead are on record with the state since 1984. 100% are drilled into bedrock, and the typical well is 340 feet deep (one in ten goes past 600 feet).
In a typical Alstead well, bedrock starts about 20 feet down, the median yield is 5 gallons per minute, 29% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open NHDES OneStop and choose Water Well.
- Enter your town and one word of your street name. Leave out the house number and the Road or Street part; a short search matches more.
- In the results, click Show for your address to see the report: total depth, depth to bedrock, casing, yield in gallons per minute, static water level, and the driller.
- Save Results exports the whole list to a spreadsheet.
Reports exist only for wells drilled since January 1984, when reporting became mandatory, and street names are as they were when the well was drilled.
Contamination sources on record in Alstead
NHDES records 1 leaking underground storage tank site, 2 unlined landfills, 1 hazardous waste site, and 2 reported spills and releases in Alstead, among 27 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 1
- leaking underground storage tank siteGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 2
- unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 1
- hazardous waste siteSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 2
- reported spills and releasesMost spills are fuel; a few are solvents or chemicals that reach the water table.
- 6
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 14
- other remediation projects
- 1
- other solid waste facility
Treatment that fits the local profile
- Lead
- Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Sodium
- Point-of-use reverse osmosis; Distillation
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Book a free water test in Alstead
A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation.
Common questions
How deep are wells in Alstead?
The typical domestic well in Alstead is 340 feet deep, based on 217 wells reported to the state since 1984. One in ten is deeper than 600 feet. 100% are drilled into bedrock.
How often should I test a private well in Alstead?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- NH DHHS WISDOM private well summaries: summaries for 11 contaminants in Alstead, up to 31 wells each. Town summaries of private well tests run by the New Hampshire Public Health Laboratories, published by NH DHHS through the WISDOM environmental public health tracking portal. Exceedance shares use New Hampshire guidance levels, which are stricter than EPA for arsenic (5 ug/L), manganese (0.3 mg/L), radon (2,000 pCi/L) and sodium (20 mg/L). Statistics for small counts are suppressed (*). Retrieved September 3, 2026.
- NHDES Water Well Inventory: 228 well records in Alstead, 217 domestic. Well construction records reported to the New Hampshire Department of Environmental Services Water Well Board. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
- NHDES OneStop regulated sites: 27 regulated sites located in Alstead. Remediation sites, underground storage tanks, solid waste facilities and potential contamination sources from the New Hampshire Department of Environmental Services OneStop database. Retrieved September 3, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.