Risks aside, the water’s still much cleaner than it used to be.

Picture this: You’re sitting on the rocks at Penn Treaty Park. It’s about a thousand degrees, and the shimmering Delaware River is just a few steps away. What do you do?

If you’ve lived in Philadelphia for more than five minutes, the thought of submerging yourself in the Delaware probably sends a chill down your spine. A century ago, the watershed was so toxic it killed the fish inhabiting it, and the stench was pungent enough that pilots complained about flying over from 5,000 feet.

But it’s been 50 years since the Clean Water Act was implemented to purify the rancid flume. Development has surged again along the banks, reconnecting Philadelphians to a waterfront that long seemed like a smelly, distant dream.

Today, environmental experts note that the river is the cleanest it’s been in decades. But they still do not advise you take a dip in the Delaware — not yet, at least.

“Would I recommend someone just jump off Penn’s Landing and swim there?” said Kate Schmidt, spokesperson for the Delaware River Basin Commission. “Even if it was OK for primary recreation, there’s other issues you need to think of.”

Riptides, shipping channels and poop in the water

Let’s just get it out of the way: The whole stream is suspect when it comes to fecal matter. Data from the Delaware River Basin Commission indicates that the section of the river running through Philly has nearly four times the sewage than anywhere else. It’s especially bad after a big rainstorm.

“The fertilizer, dog poop, herbicides and pesticides that end up on our landscape because of the way people live their lives — that gets collected by the stormwater system and ends up in the river,” said Maya van Rossum, head of the Delaware Riverkeeper Network nonprofit.

Random debris often washes into the water, from trash tumbleweeding off the streets to construction materials abandoned along the waterfront. And though the Clean Water Act helped — by treating wastewater before it gets to the river — it hasn’t completely rid the water of industrial pollutants.

Currents pose another considerable fear for would-be swimmers. The depth of the Delaware drops from about 5 feet to 30 in a short distance from the shore — and if you wade out that far, you’ll find yourself up against some pretty strong currents.

“We don’t want people to think, ‘Oh, things have improved, and it’s safe to swim,’ but don’t underestimate the power of the water,” Schmidt said. “People have drowned in the water without a life jacket on.”

Also watch out for boats, she added. Philadelphia is a major port, and if you’re not careful, you could literally swim into a shipping channel and get absolutely annihilated by a gargantuan sea vessel.

Every other section of the Delaware? Jump on in

For the record, Philadelphia is the only spot along the Delaware River that has been officially deemed unsafe. The EPA has classified the remaining sections of the waterway in both directions as safe enough for “primary recreation.”

To regulate the 301-mile waterway, the EPA divides it into six zones. Our lovable metropolis is set firmly in Zone 3.

Think of it like the do-not-submerge zone.

“Around Philadelphia, we say secondary contact is OK, but not primary,” Schmidt said. “That’s because of things like debris and combined sewer overflows in the water.”

Officials instead recommend boating, kayaking and maybe some light wading near the shore.

But that might soon change. Local environmental advocacy groups are lobbying lawmakers to change up Zone 3’s designation — which would necessitate cleaning up the watershed to the point where Philadelphians can bathe without harm.

The battle to change our designation

Van Rossum, who calls herself the Delaware Riverkeeper, is leading the charge to get a swimming designation approved around Philly.

She hypothesizes that people are already using the waterway for primary recreation — so they’d better make it safe for them to do it.

“The reality is that people are swimming,” van Rossum said. “We need that formal designation so that we are assured that when people are out there swimming, they know that the government is putting in place the best protections.”

So far, she’s released a recreation survey for folks in the Philadelphia area to identify how they use the watershed, and she petitioned the Delaware River Basin Commission to change its designation.

Schmidt, of the DRBC, agrees: “We’re seeing that people are using the water for some more primary contact type recreation, like jet skiing,” she said. “So if people are using it that way, does the designated use of that area need to be upgraded?”

The Commission is looking into it. They’ve launched a brand new bacterial monitoring program in Zone 3. Five times a month, DRBC staffers will test eight points around Philadelphia for contaminants — and if they find that the water is clean enough for primary rec, they’ll ask the EPA to switch designations.

“It’s a process that’s underway,” Schmidt said. “We need some more data to be collected and more discussion before we make a recommendation.”