When you are in escrow for a home, or deep in planning a new home, you may learn something new. You may find that your parcel is in an “Alquist-Priolo Earthquake Fault Zone.”

This may appear on the disclosure report or a plan check comment. The news sounds terrifying, and you think, “Does it imply that you can’t construct?”

Let’s be clear right off the bat: being in a fault zone does not mean development is not possible. It initiates a need for further investigation. That investigation addresses one simple question: does a fault trace exist in your building footprint?

This article explains what the Alquist-Priolo Act is and how we map the fault zones. It also explains fault investigation and the consequences of discovering fault beneath your site.

It is an important act of California law that regulates development near active faults since 1972, after the San Fernando earthquake in 1971. The core purpose is to prevent building human-occupied structures across an active fault.

The Act addresses surface fault rupture. The ground physically breaking and offsetting along a fault line during an earthquake is surface fault rupture. A structure straddling a rupturing fault can torn apart a structure straddling over it.

This is distinct from earthquakes, liquefaction, or landslides. California’s Seismic Hazards Mapping Act regulates such hazards separately.

Groundwater loaded with sulfates is one of concrete’s worst enemies. Sulfate attack makes concrete swell, crack, and slowly fall apart — damaging foundations, drilled shafts, and buried structures. Testing the groundwater chemistry tells engineers which cement type and concrete mix to use. The report should include a water quality analysis where it indicates a high groundwater level.

De-watering or pumping is necessary for deep excavations where water will be below the water level. However, the water cannot be pumped anywhere without treatment. Typically, discharge to storm drains or waterways requires permits and testing.

Water quality is assessed by testing and must comply with the quality limits. If this is not achieved, then the project may be held up in potentially costly delay; stop-work orders and fines may be issued.

The right environmental inspections prevents project delays and avoid risky project budget issues. Properly framed inspections safeguard schedules, jobs and your project budgets.

The Centers for Disease Control and Prevention (CDC), however, offers guidance on private well testing and preventing waterborne diseases. EPA also provides current PFAS and drinking water information. The Safe Drinking Water Act establishes enforceable standards for public water systems set by the U.S. Environmental Protection Agency (EPA).

Water testing is important for public health too. Getting filthy drinking water with germs is a significant health threat. For example, E. coli or heavy metals, lead, PFAS,

Construction is a regulated source of water pollution in itself. Grading and digging can cause muddy runoff, which is detrimental to the storm and stream systems. Thus, construction sites greater than 1 acre will require stormwater permits under the EPA’s National Pollutant Discharge Elimination System. These rules are under the jurisdiction of the State Water Resources Control Board and its regional boards in California.

Old contamination comes on top. Past plumes can pollute groundwater and persist for decades. It generally comes as a consequence of former industrial sites, leaking underground storage tanks, or past dumping.

This is why, as part of a Phase II environmental site assessment, we take soil and groundwater samples. Typically, we need a Phase II assessment.

Appropriate wall type according to your property depends upon the slope shape, the soil, groundwater, and site access. A geotechnical investigation determines the above-mentioned parameters. On fire-scarred lots, do not assume a soils report written before the fire is still valid.

Burned slopes behave differently compared to the real conditions. So, most cities and counties will require an updated soils study before a new retaining wall approval.

For testing the water quality, you should follow the methods below:

Field tests are straightforward, consisting of measurements of the pH, temperature, dissolved oxygen and turbidity using field pH, temperature, and turbidity meters and probes. Testing can be quick and can be helpful for initial assessment. But there is only an approximation of results and no real proof.

The monitoring wells enable multiple sampling from one point over time. Monitoring of contamination plumes, verifying cleanup effectiveness, and observing groundwater in deep excavations is possible with groundwater monitoring wells. The U.S. Geological Survey (USGS) has abundant groundwater data that are often used to supplement site-specific monitoring programs.

For legal and/or engineering significance, results from certified laboratory analysis are preferred. We take samples in a controlled environment with compliance rules and document the chain of custody. We then perform analysis that uses EPA-approved methods at an accredited analytical laboratory. It is the standard to comply with for drinking water, discharge permits, and environmental site assessments.

Instrumentation includes in-line sensors and data loggers. These instruments provide real-time monitoring for treatment plants and critical infrastructure. They are able to detect water quality issues when they occur.

You should identify every authority over your project early. You will know the exact requirements from each of them, and it will not delay the project. Water testing requirements come from several overlapping authorities:

• Federal public water supplies are under the Safe Drinking Water Act. Surface Water discharge is regulated by the Clean Water Act and the NPDES program. The EPA operates both departments.
• State of California (California State Water Resources Control Board) has set the discharge permits and water quality goals. Nationwide, utilities follow industry standards as developed by organizations such as the American Water Works Association (AWWA).
• Transportation and public works: The agencies establish their own regulations concerning work in their area. Caltrans has comprehensive requirements regarding stormwater and water quality for development located in the State highway right of way. Every project should follow Los Angeles grading and drainage codes from LADBS and the city’s Stormwater Ordinance.

Consider professional testing in these situations:

• Before buying or developing property — as part of Phase I/II environmental due diligence
• Before foundation design in areas with shallow groundwater — to check for corrosion and sulfate exposure
• Before and during construction de-watering — to get and keep discharge permits
• After suspected contamination — nearby industrial activity, old tanks, or unusual odors and staining
• For ongoing permit compliance — scheduled sampling under NPDES or local discharge permits
• For private wells and small systems — routine yearly testing for bacteria and nitrates, following EPA guidance for private wells

A qualified environmental or geotechnical firm follows a defined process:

1. Examine and devise a sampling plan
2. Correctly collect samples and maintain them appropriately
3. Maintain chain of custody, submit samples to an approved laboratory
4. Interpret the results

Without a professional engineer, raw lab data and design advice or compliance results don’t have value. Home test kits are suitable for basic well screening; however, you can’t obtain a permit based on the results.

Water quality testing is beneficial for waterproofing systems and the communities above. Certified testing provides engineering decisions from an unknown situation. Such as for selecting sites for a foundation, dewatering program, or simply conducting a due diligence survey

Do you need water quality testing, groundwater monitoring, or environmental compliance support at your project? Call in our group of accredited Engineers or Environmental experts today for a cost-free expert consultation and estimate. We will develop a sampling program that meets all the agencies’ requirements and have a voice in your project.

How much time does it take to test?

Field tests provide results immediately. However, the standard laboratory usually takes 5 to 10 business days, with rush options available.

What are your costs for water quality testing?

Basic lab panels start at a few hundred dollars. Full contamination assessments with monitoring wells cost more. Either way, testing is always cheaper than the failure or violation it prevents.

Do I need water testing for a construction project?

If your project involves dewatering, shallow groundwater, stormwater permits, or an environmental site assessment — yes.

Can water quality really affect my foundation?

Absolutely. Sulfate attack and chloride-driven corrosion are leading causes of early foundation and buried-utility failure.