Why Plumbing Costs Jump in Early December

December Starts With a Pricing Shift

Every plumbing contractor feels it. Early December brings a wave of restocking, jobs that need to be closed before the holidays, and suppliers moving huge volumes of high-turnover items.

This is also when plumbing costs jump faster than most teams expect.

Not because anything is wrong. But because December forces suppliers to update pricing more aggressively than any other month.

High-turnover items move first. And that movement usually goes unnoticed.

The Problem: Supplier Updates Hide Inside Familiar Numbers

Plumbing materials have predictable patterns. Copper. PVC. Brass fittings. Consumables. Most teams know the pricing by feel.

That familiarity is exactly why supplier updates slip through.

Early December creates a perfect storm:

• restocking spikes

• shortage cycles start

• discount windows change

• substitutions increase

• next-year pricing quietly rolls in

• invoices arrive in bulk

The totals look believable. The SKUs look familiar. The drift hides in the movement.

By the time anyone notices, margin has already shifted.

The Solution: Compare Current Prices to Baselines

You do not need a full audit to see where costs have moved. You need a baseline.

Here’s the method top plumbing operators use in early December:

1. Pull your September price list

That is your cleanest quarter-over-quarter baseline.

2. Compare it to your first December invoices

This shows the true movement suppliers rarely announce.

3. Focus on the top 20 items

These SKUs cause more December drift than anything else.

4. Flag anything that moved more than two percent

Small December changes stack fast when restocking volume is high.

This baseline comparison is the fastest way to see what December is doing to your margins.

Get My Supplier Billing Risk Scorecard

If you want to understand where your plumbing costs are shifting — and how exposed your process is during December — start here:

Get My Supplier Billing Risk Scorecard: https://www.3rd-armor.com/supplier-billing-risk-scorecard

It shows where your numbers moved, where supplier updates hit hardest, and what margin is at risk this month.