Engineers present model, recommend stepped flushing, targeted cleaning and selective replacements to tackle Waldwick's rusty-water complaints

Consulting engineers presented a calibrated hydraulic model of Waldwick's water distribution and a stepped plan to reduce chronic discoloration and aesthetic complaints.

The consultants said they spent about 18 months compiling operator data, mapping complaints and building a 3-D model to replicate the borough's flow patterns. They said aging metallic mains and changes in how sources are operated have altered flow paths, producing localized pockets of low velocity where corrosion and sediment accumulate.

"Almost all infrastructure of this kind is composed of materials that tend to age and degrade over time," the lead presenter said, explaining the model's purpose: to forecast how operational changes or repairs would affect downstream water quality before the borough spends capital.

The team recommended a tiered approach. First, expand the existing hydrant-flushing program in frequency and intensity and continue it as an operational practice; consultants stressed flushing should avoid freezing conditions and summer peak demand. Second, where complaints persist, use intensified or unidirectional flushing to induce scouring velocities in targeted lengths of pipe. Third, if flushing results and follow-up samples indicate persistent turbidity or tuberculation, perform selective test pitting and pipe couponing to measure wall thickness. Where pipe integrity is adequate, the borough could pursue cleaning-and-lining; where wall thickness is too low, selective replacement with ductile iron or approved plastic piping would be recommended.

The presenters emphasized that pigging (mechanical swabbing) and unidirectional flushing are more expensive than routine hydrant flushing but remain far cheaper than full main replacement. They recommended including selective couponing in contract scopes so crews can verify pipe integrity before higher-velocity cleaning operations.

Consultants framed timing and risk: continue current flushing through spring so the borough collects additional data, use summer for planning, and schedule field operations in fall when pumping demand is lower. They characterized the condition as long-term and chronic rather than an acute public-health emergency.

On water safety, the consultants said Waldwick's treated sources meet primary regulatory limits and that the discoloration residents experience is driven largely by secondary contaminants (dissolved iron and manganese). "These are secondary contaminants that cause taste, odor and staining; at the concentrations we observe they are not known to be a health risk," a presenter said, noting state and federal sampling programs remain in place and PFAS treatment installed after 2024 has reduced PFAS to nondetect at sources.

Council members and staff reported the borough has already implemented much of the recommended operational work: directional flushing that began in January, valve replacements (about 35 over the past two years) and hydrant maintenance. The water superintendent said the borough is roughly halfway through this winter'to-spring flush program, with weather-driven pauses when temperatures fall below 32 F.

Residents asked about the borough's use of complaint data and about household sampling. Consultants explained the borough's web form logs address-level complaints that are incorporated into the model and are useful for targeting; they said hydrant/distribution sampling gives a more conservative, system-level picture than isolated household faucet draws, which require disciplined sampling protocols to be diagnostic. The consultants said they have taken some household samples during high-complaint periods but prioritize systematic distribution sampling.

On materials and lining, a resident asked about microplastics from plastic-lined pipe. The consultants said scientific evidence on chronic health impacts of microplastics is unclear and that plastic is one of several lining materials; the borough could explicitly avoid plastic lining if it prefers.

Next steps described in the meeting: continue and log flushing results, aggregate sampling and complaint data through summer, consider targeted couponing/test pitting at a half-dozen suspect locations, and return to the council with specific, site-level recommendations and cost estimates in the fall. The consultants also offered to hold a workshop with residents to review intensified-flushing outcomes and any proposed field sampling.

Votes at a glance: during the same session the council approved a consent agenda and several routine resolutions by roll call; an ordinance (ordinance 2026-03) was introduced on first reading with a public hearing scheduled for April 28, 2026; council also introduced the 2026 municipal budget (proposed $17,050,999) for public hearing and adoption at a later meeting.

The consultants and borough staff encouraged residents still experiencing discoloration to continue reporting their issues through the borough's complaint form so the team can correlate ongoing events with hydrate flushing and model outputs. The council did not take a formal motion on capital funding for pipe replacements during the meeting; funding decisions will follow targeted recommendations and further review.

Sources and attributions in this report are limited to speakers who appear in the meeting record and are named or functionally identified in the transcript.