Verification Savings Calculator
How many of your unknowns need a site visit?
Enter three numbers from your inventory. You'll see what statistical analysis could save you in field costs, and whether your crew can finish before the November 1, 2027 deadline.
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Reading your results
The subset
With statistical analysis, you verify a random sample of your unknowns instead of all of them. If the sample comes back with no lead or GRR, your state may let you classify the rest as non-lead. The calculator sizes the sample at a 95% confidence level and a 5% margin of error, which many states use. Check your state's requirement before you plan around it.
The savings
The dollar figure is field cost only: the lines you wouldn't have to verify, times your cost per line. It doesn't include the cost of the analysis itself or any software.
The timeline
The chart shows how far your crew gets by November 1, 2027 at the pace you entered. Anything past the dashed line is still unknown at the deadline, and unknowns count toward your replacement pool.
Statistical analysis or predictive modeling?
Statistical analysis
This is what the calculator estimates. It works best when you have no reason to expect lead or GRR in your system. If lead turns up in the sample, the remaining lines stay unknown.
Predictive modeling
If you know or suspect you have lead or GRR, predictive modeling is usually the better fit. It gives every unknown line a probability of being lead, so your crews dig where lead is most likely and skip the rest.
How predictive modeling works
What to know about unknowns under the LCRI
Unknowns carry real obligations
Under the LCRI, service lines of unknown material count toward your replacement pool alongside lead and GRR lines. The more unknowns you have on November 1, 2027, the larger your annual replacement target.
Your baseline inventory is due 11/1/2027
It has to include connector materials as well as service lines. Connectors are often missing from inventories built for the 2024 deadline.
Non-lead lines will be checked again
Lines classified as non-lead, including those classified through statistical analysis or modeling, go into a validation pool. A random subset has to be physically inspected by the end of 2034.
Earlier work may reduce that later
EPA's August 2026 inventory guidance notes that utilities that model before the compliance date may be able to ask their state for a validation waiver, if they used field inspections at least as rigorous as the LCRI validation process.
Every state handles this differently
Primacy agencies decide which methods they accept, what confidence level they require, and what happens if lead turns up in a sample. Confirm your state's rules before you commit field budget.
Predictive modeling in action
El Paso Water started 2025 with nearly 130,000 unknown service lines. After field-verifying about 60,000 lines in six months, the utility turned to 120Water predictive modeling. More than 40,000 unknowns were classified as non-lead, and El Paso ended the year with fewer than 13,000 unknowns.
Frequently Asked Questions
Many states accept it, but requirements vary: which lines qualify, the required confidence level, and what happens if lead turns up. Check your primacy agency's guidance, or ask us and we'll tell you what we know about your state.
The remaining unknowns can't be classified as non-lead from that sample. Depending on your state, you may be able to model the affected area separately or continue verifying. If you expect lead, predictive modeling is usually the better starting point.
Costs depend on your system size, your data and which services you need. We'll put together a full comparison with your numbers, including non-lead validation.
Yes. 120Water Field Services can work alongside your crew or take on verification work directly.
See the full picture for your system
The calculator covers field work and timing. We can go through the rest with you: total cost, non-lead validation, and what your state allows.