diff --git a/package.json b/package.json
index 832b3d248a..734ca941d2 100644
--- a/package.json
+++ b/package.json
@@ -48,15 +48,14 @@
     "@ethersproject/address": "^5.0.8",
     "@ethersproject/bignumber": "^5.1.1",
     "@ethersproject/bytes": "^5.0.8",
-    "@typechain/ethers-v5": "9.0.0",
-    "@types/prompts": "^2.0.14",
-    "@types/yargs": "^17.0.9",
-    "dotenv": "^10.0.0",
-    "ethers": "^5.1.0",
-    "ts-node": "^10.2.1",
-    "typechain": "7.0.0"
+    "ethers": "^5.1.0"
   },
   "devDependencies": {
+    "ts-node": "^10.2.1",
+    "dotenv": "^10.0.0",
+    "@typechain/ethers-v5": "9.0.0",
+    "@types/yargs": "^17.0.9",
+    "typechain": "7.0.0",
     "@arbitrum/nitro-contracts": "1.0.0-beta.5",
     "arb-bridge-peripherals": "1.0.10",
     "@nomiclabs/hardhat-ethers": "^2.0.4",
diff --git a/scripts/instantiate_bridge.ts b/scripts/instantiate_bridge.ts
index 98cc34ae69..e20c083c02 100644
--- a/scripts/instantiate_bridge.ts
+++ b/scripts/instantiate_bridge.ts
@@ -59,25 +59,25 @@ export const instantiateBridge = (
     throw new Error('need ARB_KEY var')
   }
 
-  let networkID = args.networkID
-  if (!networkID) {
+  let l2NetworkID = args.networkID
+  if (!l2NetworkID) {
     console.log(
       'No networkID command line arg provided; using network',
       defaultNetworkId
     )
 
-    networkID = defaultNetworkId
+    l2NetworkID = defaultNetworkId
   }
-  const isL1 = isDefined(l1Networks[networkID])
-  const isL2 = isDefined(l2Networks[networkID])
+  const isL1 = isDefined(l1Networks[l2NetworkID])
+  const isL2 = isDefined(l2Networks[l2NetworkID])
   if (!isL1 && !isL2) {
-    throw new Error(`Unrecognized network ID: ${networkID}`)
+    throw new Error(`Unrecognized network ID: ${l2NetworkID}`)
   }
   if (!isL2) {
-    throw new Error(`Tests must specify an L2 network ID: ${networkID}`)
+    throw new Error(`Tests must specify an L2 network ID: ${l2NetworkID}`)
   }
 
-  const l2Network = l2Networks[networkID]
+  const l2Network = l2Networks[l2NetworkID]
   const l1Network = l1Networks[l2Network.partnerChainID]
 
   if (!l1Network) {
@@ -86,14 +86,26 @@ export const instantiateBridge = (
     )
   }
 
-  if (!l1Network.rpcURL) {
-    throw new Error('L1 rpc url not set (see .env.sample or networks.ts)')
-  }
-  if (!l2Network.rpcURL) {
-    throw new Error('L2 rpc url not set (see .env.sample or utils/networks.ts)')
-  }
-  const ethProvider = new JsonRpcProvider(l1Network.rpcURL)
-  const arbProvider = new JsonRpcProvider(l2Network.rpcURL)
+  const l1Rpc = (() => {
+    if (l2NetworkID === 42161) return process.env['MAINNET_RPC'] as string
+    if (l2NetworkID === 421611) return process.env['RINKEBY_RPC'] as string
+    if (l2NetworkID === 1338) return 'http://127.0.0.1:8545/'
+    throw new Error(
+      'L1 rpc url not set (see .env.sample or networks.ts) or chain id not supported'
+    )
+  })()
+  const l2Rpc = (() => {
+    if (l2NetworkID === 42161)
+      return process.env['ARB_ONE_RPC'] || 'https://arb1.arbitrum.io/rpc'
+    if (l2NetworkID === 421611)
+      return process.env['RINKARBY_RPC'] || 'https://rinkeby.arbitrum.io/rpc'
+    throw new Error(
+      'L2 rpc url not set (see .env.sample or networks.ts) or chain id not supported'
+    )
+  })()
+
+  const ethProvider = new JsonRpcProvider(l1Rpc)
+  const arbProvider = new JsonRpcProvider(l2Rpc)
 
   const l1Signer = (() => {
     if (l1PkParam) {
diff --git a/scripts/testSetup.ts b/scripts/testSetup.ts
index 69c5bb40ad..b2202d47ea 100644
--- a/scripts/testSetup.ts
+++ b/scripts/testSetup.ts
@@ -88,7 +88,6 @@ export const getCustomNetworks = async (
     isCustom: true,
     name: 'EthLocal',
     partnerChainIDs: [l2NetworkInfo.chainId],
-    rpcURL: l1Url,
   }
 
   const l2Network: Omit<L2Network, 'tokenBridge'> = {
@@ -106,7 +105,6 @@ export const getCustomNetworks = async (
     isCustom: true,
     name: 'ArbLocal',
     partnerChainID: l1NetworkInfo.chainId,
-    rpcURL: l2Url,
     retryableLifetimeSeconds: 7 * 24 * 60 * 60,
   }
   return {
diff --git a/src/lib/dataEntities/networks.ts b/src/lib/dataEntities/networks.ts
index 8db5886ea5..624e85c5a2 100644
--- a/src/lib/dataEntities/networks.ts
+++ b/src/lib/dataEntities/networks.ts
@@ -16,13 +16,10 @@
 /* eslint-env node */
 'use strict'
 
-import dotenv from 'dotenv'
 import { SignerOrProvider, SignerProviderUtils } from './signerOrProvider'
 import { ArbSdkError } from '../dataEntities/errors'
 import { SEVEN_DAYS_IN_SECONDS } from './constants'
 
-dotenv.config()
-
 export interface L1Network extends Network {
   partnerChainIDs: number[]
   blockTime: number //seconds
@@ -40,7 +37,6 @@ export interface Network {
   chainID: number
   name: string
   explorerUrl: string
-  rpcURL: string
   gif?: string
   isCustom: boolean
 }
@@ -135,7 +131,6 @@ export const l1Networks: L1Networks = {
     explorerUrl: 'https://etherscan.io',
     partnerChainIDs: [42161],
     blockTime: 14,
-    rpcURL: process.env['MAINNET_RPC'] as string,
     isCustom: false,
   },
   1338: {
@@ -144,7 +139,6 @@ export const l1Networks: L1Networks = {
     explorerUrl: 'https://etherscan.io',
     partnerChainIDs: [42161],
     blockTime: 1,
-    rpcURL: 'http://127.0.0.1:8545/',
     isCustom: false,
   },
   4: {
@@ -153,7 +147,6 @@ export const l1Networks: L1Networks = {
     explorerUrl: 'https://rinkeby.etherscan.io',
     partnerChainIDs: [421611],
     blockTime: 15,
-    rpcURL: process.env['RINKEBY_RPC'] as string,
     isCustom: false,
   },
 }
@@ -168,7 +161,6 @@ export const l2Networks: L2Networks = {
     tokenBridge: mainnetTokenBridge,
     ethBridge: mainnetETHBridge,
     confirmPeriodBlocks: 45818,
-    rpcURL: process.env['ARB_ONE_RPC'] || 'https://arb1.arbitrum.io/rpc',
     isCustom: false,
     retryableLifetimeSeconds: SEVEN_DAYS_IN_SECONDS,
   },
@@ -181,7 +173,6 @@ export const l2Networks: L2Networks = {
     tokenBridge: rinkebyTokenBridge,
     ethBridge: rinkebyETHBridge,
     confirmPeriodBlocks: 6545, // TODO
-    rpcURL: process.env['RINKARBY_RPC'] || 'https://rinkeby.arbitrum.io/rpc',
     isCustom: false,
     retryableLifetimeSeconds: SEVEN_DAYS_IN_SECONDS,
   },