Regarding WSSC’s Chuck Brown’s response to my letter to the Independent, I think it is a mistake — operationally, legally, and reputationally — for a public utility to state that there was “no risk to the public drinking water quality because of this incident” during the Bond Mill Road water main repair. Not because every repair results in contamination — most do not — but because risk in drinking water systems is conditional, dynamic, and governed by physics and regulatory safeguards. It is never absolute.
Hydraulic and Contamination Risk
When a potable water main leaks, system pressure drops and surrounding soils become saturated. In this case, the potable main was vertically co-located beneath a raw water source. If raw water or contaminated groundwater is present above or adjacent to the potable main, gravity and hydrostatic pressure favor downward migration into the excavation zone. During repair, when the pipe is cut open, negative pressure conditions can occur. That pressure differential can draw surrounding water or soil contaminants into the potable system — a well-documented mechanism known as back-siphonage and intrusion during depressurization. Even if chlorination occurs after the repair, contaminants introduced during low-pressure events may migrate into service laterals, dead ends, or storage systems before residual disinfection stabilizes.
Pressure fluctuations are unpredictable. Zero risk is therefore not technically defensible. This repair reportedly took approximately 19 hours or more to complete, with additional time following discovery of the leak. The longer a depressurized main remains exposed, the greater the potential intrusion window. Compounding this concern, crews were initially provided incorrect depth information for the pipe, extending excavation time. The potable infrastructure in this area dates to the 1970s — approximately 50 years old — further increasing vulnerability to joint failure or bedding instability.
Regulatory and Liability Exposure
Under the Safe Drinking Water Act and Maryland’s implementing regulations (COMAR 26.04.01 – Quality of Drinking Water), any depressurized potable main exposed to potential contamination is presumed to carry contamination risk until verified otherwise through proper isolation, disinfection, and bacteriological sampling. Customers were not issued a boil water advisory. It is unclear whether bacteriological clearance sampling was performed prior to restoring service. Transparency regarding sampling results would strengthen public confidence. If a utility publicly asserts “no risk” and contamination is later detected, legal exposure increases and credibility erodes. Risk in water systems is controlled and mitigated — not declared nonexistent.
Hydraulic Pressure Differential Reality
When raw water infrastructure is located above potable infrastructure, gravity favors downward flow. If the raw water line develops leakage — whether from excavation disturbance or pre-existing defect — surrounding soils can become saturated. Excavation reduces soil confinement. If potable system pressure drops below hydrostatic pressure, intrusion becomes physically possible. This is not speculation. It is basic fluid mechanics. Physics alone makes zero risk untenable.
Soil and Trench Stability Concerns
Leaking water beneath a raw source creates saturated trench walls, reduced soil bearing capacity, increased cave-in risk, and bedding destabilization. The installation of a concrete trench protection system during this repair underscores the depth and instability of the excavation. Disturbance in vertically co-located utilities increases the risk of joint stress, settlement, and future structural failure. Adjacent utilities — including gas infrastructure — can also be compromised during prolonged excavation events, creating cascading risk.
Infrastructure Integrity and Co-Location Risk
Where utilities are vertically co-located, crews may need to undercut upper lines. Vibration, compaction variability, and disturbed bedding elevate long-term settlement risk. These are recognized infrastructure management hazards, not theoretical concerns.
Communications and Public Trust
If customers later learn that a potable main was leaking beneath a raw water source and were told there was “no risk,” trust will suffer. The recent Bond Mill Road Raw Water Main Project and the WSP report emphasized that credibility is as critical as engineering competence. Effective risk communication does not require alarming the public. It requires precision. The defensible language in such circumstances is: “The risk to public health is low and has been mitigated through isolation, disinfection, and bacteriological testing.” That statement acknowledges reality while reinforcing safeguards.
It is also concerning that crews reportedly had difficulty locating the potable pipe, approximately 35 residents experienced water outages without direct notice, and the broader West Laurel community was not informed of potential depressurization exposure. Transparent communication strengthens authority; categorical assurances weaken it.
Risk Management Framework
As suggested in the WSP report, WSSC should align this condition within its GIS risk framework. Vertical co-location where a pressurized potable main lies beneath a non-potable or raw source should be flagged as a high-risk proximity condition. Risk scoring should incorporate vertical separation distance, soil permeability, depth of burial, pressure differential potential, duration of depressurization, and historical leak frequency. Notably, four water main leaks have occurred on Bond Mill Road since completion of the recent project — a pattern that warrants analysis.
The Bottom Line
You cannot credibly state “no risk” because pressure changes create intrusion potential, excavation increases exposure pathways, regulations assume contamination possibility until clearance is verified, soil physics favors downward migration, and liability exposure exists if assurances prove inaccurate. In water infrastructure management — as in any professional engineering discipline — risk is managed, mitigated, and verified. It is never eliminated.
The opinions expressed in From Where I Stand pieces are the author’s own. Streetcar Suburbs reserves the right to edit From Where I stand submissions for brevity and clarity.