Well Water in Corrales, New Mexico

Sandoval County · Population ~8,500 · Aquifer: Rio Grande Alluvium

Hardness: Moderate to High

The Nitrate Problem

When every home has both a well pulling water up and a septic system pushing waste down, contamination is a matter of physics. The primary water quality concern in Corrales is nitrate contamination from septic systems.

An NMED study found nitrate-nitrogen levels in Corrales wells reaching up to 6.5 mg/L. The EPA maximum contaminant level (MCL) is 10 mg/L, and natural background in the area is just 0.5-2 mg/L. Some wells are already at 65% of the federal limit — and nitrate levels tend to rise over time as more septic systems age.

Nitrates are especially dangerous for infants (blue baby syndrome) and pregnant women. They cannot be removed by boiling — boiling actually concentrates them.

Village Protections

Corrales has recognized this risk and implemented protective regulations:

• One dwelling per acre minimum — to ensure adequate separation between wells and septic systems
• Well setbacks: Wells must be at least 50 feet from any septic tank and 100 feet from any drain field
• Free well testing: The Village periodically offers free water testing for residents

These measures help, but they don't eliminate the risk — especially as septic systems age and the number of homes has increased over decades.

Other Water Quality Issues

Beyond nitrates, Corrales wells commonly show:

• Hardness — the Rio Grande alluvium produces moderately hard to hard water
• Manganese — causes brownish-black staining on fixtures and laundry
• Iron — rusty staining, metallic taste
• High total dissolved solids (TDS) — general mineral content above ideal levels
• Bacteria — shallow water table makes wells more vulnerable to surface contamination

Arsenic is generally less of a concern in Corrales than in surrounding communities, thanks to the alluvial (river-deposited) geology. But it should still be tested at least once.

Testing and Treatment

Every Corrales well should be tested annually for bacteria and nitrates at minimum. Given the septic-system risk, this is not optional — it's essential.

If nitrates are elevated, reverse osmosis is the standard treatment. Standard carbon filters do not remove nitrates. For iron and manganese, oxidation filtration or water softeners are effective. For bacteria, UV disinfection or chlorination.

Take advantage of the Village's free testing when it's offered. For comprehensive testing, see our testing guide.

Local treatment companies like TEER Water specialize in Corrales installations and understand the specific water chemistry.