Your irrigation water affects everything—nutrient availability, soil structure, and long-term productivity. This guide covers what to test, what the numbers mean, and how to fix common problems.
Every irrigation adds more than water to your soil. Dissolved minerals accumulate season after season. If your water contains 200 ppm sodium and you apply 3 acre-feet annually, you're adding over 1,600 pounds of sodium per acre each year. That compounds.
California groundwater quality varies dramatically by region, depth, and even between adjacent wells. What worked for your neighbor might not work for you. And conditions change—drought concentrates minerals, new wells tap different aquifers.
The good news: most water quality problems are manageable once you understand them. The bad news: ignoring them leads to declining yields, soil degradation, and expensive remediation down the road.
What to test for and what the numbers mean
| Parameter | Optimal | Concern | Critical | Impact |
|---|---|---|---|---|
| pH | 6.0 - 7.0 | > 7.5 | > 8.0 | High pH reduces nutrient availability, especially iron, zinc, and manganese. Causes scale buildup in drip systems. |
| Bicarbonates (HCO₃) | < 100 ppm | 100 - 250 ppm | > 250 ppm | Raises soil pH over time, binds calcium and magnesium, creates surface crusting, reduces fertilizer efficiency. |
| Sodium (Na) | < 70 ppm | 70 - 150 ppm | > 150 ppm | Destroys soil structure, disperses clay, competes with beneficial cations. Difficult to remediate once accumulated. |
| Chloride (Cl) | < 100 ppm | 100 - 250 ppm | > 250 ppm | Accumulates in leaf tissue, causes marginal burn, reduces yield. Some crops more sensitive than others. |
| EC (Electrical Conductivity) | < 0.75 dS/m | 0.75 - 2.0 dS/m | > 2.0 dS/m | Total salt load. High EC increases plant water stress and adds to soil salinity with every irrigation. |
| SAR (Sodium Adsorption Ratio) | < 3 | 3 - 9 | > 9 | Indicates sodium hazard relative to calcium and magnesium. High SAR = soil structure problems. |
| Boron (B) | 0.2 - 0.5 ppm | 0.5 - 1.0 ppm | > 1.0 ppm | Essential at low levels, toxic at high levels. Narrow range between deficiency and toxicity. |
Common issues by California agricultural region
How to address common water quality problems
Inject acid to lower pH to 6.0-6.5 before reaching emitters. Neutralizes bicarbonates.
Calcium displaces sodium from soil exchange sites. Combine with leaching to remove displaced sodium.
Calculate leaching fraction, apply excess water to push salts below root zone. Improve drainage.
High calcium + high pH = calcium carbonate scale. Acidification prevents formation.
Borreplex OA is an organic acid blend specifically designed for California irrigation water. It acidifies water, neutralizes bicarbonates, reduces sodium impact, and frees bound nutrients—all while being compatible with organic certification.
Learn more about Borreplex OA →A comprehensive water test is the first step to solving water quality problems. We'll help you understand your results and develop a treatment plan.